Something important to consider about being Jewish is it’s not just a religion. It’s a religion and an ethnicity and a culture and a people and an identity. It’s a lot of things all rolled into one. Jews had been discriminated against because of their identity for centuries. This discrimination caused a segregation in society. Jews generally had a very strong sense of identity about their said Jewish-ness.

An important distinction is Eastern vs. Central European Jews. Many people before the 20th century lived in all Jewish neighborhoods/villages/towns/areas. These small all/mostly Jewish towns were called shtetls (the Yiddish word for town). They were almost all in Eastern Europe. However the Jewish populations in these places were much more likely to speak Yiddish. The Eastern European Jews were less educated than their Central European brothers.

Eva Hoffman, an American-Polish writer laments;

The destruction was nowhere more complete than in the numberless Polish shtetls, those villages and small towns that dotted the Polish landscape and that were sometimes partly, sometimes preponderantly, Jewish. The villages are still there, many of them lovely enough to justify geographic longing; the towns can be found, often transformed into bleakness by postwar poverty and socialist architecture. A few synagogues still stand, some of them crumbling from neglect and disuse, others preserved and restored to their former dignity. Occasionally, outside the borders of a village, there is a small Jewish cemetery, with weeds and vegetation climbing up the crooked headstones. A Polish farmer will point out a copse where the Jews were rounded up by the Nazis and shot; in a few places, modest monuments have been erected to those who perished. Relics, scattered and enigmatic, as of a lost ancient civilization. But the pulsing Jewish world that was here, the small shops and stalls, the bustle of people, carts, horses, the sounds of Yiddish and Hebrew--these are no more. The Jews, a Polish poet wrote, "were captured in the hot act of life." That life can almost be intuited beyond the curtain of abrupt absence. We think we can almost cross the curtain; but we cannot.

We learn more about shtetls from the United States Holocaust Memorial Museum;

In 1933 the largest Jewish populations were concentrated in eastern Europe, including Poland, the Soviet Union, Hungary, and Romania. Many of the Jews of eastern Europe lived in predominantly Jewish towns or villages, called shtetls. Eastern European Jews lived a separate life as a minority within the culture of the majority. They spoke their own language, Yiddish, which combines elements of German and Hebrew. They read Yiddish books, and attended Yiddish theater and movies. Although many younger Jews in larger towns were beginning to adopt modern ways and dress, older people often dressed traditionally, the men wearing hats or caps, and the women modestly covering their hair with wigs or kerchiefs.

So to address your question of ‘recanting’ their Jewish-ness, it was not quite realistic in Eastern Europe. Being Jewish was such a huge part of their identity, to recant it would mean what? They spoke Yiddish, a clear giveaway for being Jewish and thus persecution. Everyone they were close to lived in Jewish neighborhoods, their entire lives were often in their shtetls. Many still dressed in traditionally. To recant it would mean to give up everything and everyone they had ever known. It may have been attempted but it’s chances of success were not high.

And then we have the Central European Jews. The United States Holocaust Memorial Museum website states;

Though they lived almost exclusively in villages and small towns at the beginning of the nineteenth century, by 1900 the majority of—though by no means all—German Jews lived in big cities. In 1910, 60 percent of German Jews lived in urban areas with more than 100,000 inhabitants. In 1933 more than 70 percent of German Jews resided in cities. Only 10 percent of German Jews lived in the countryside, while 20 percent lived in smaller towns and villages. According to a 1925 census, 564,973 registered Jews lived in the Weimar Republic, 71.5 percent of whom resided in Germany’s largest province, Prussia.

Central European Jews were much more urban and “integrated” than their neighbors to the East. Once again, the United States Holocaust Memorial Museum;

In Comparison, the Jews in western Europe—Germany, France, Italy, the Netherlands, and Belgium—made up much less of the population and tended to adopt the culture of their non-Jewish neighbors. They dressed and talked like their countrymen, and traditional religious practices and Yiddish culture played a less important part in their lives. They tended to have had more formal education than eastern European Jews and to live in towns or cities.

Jews could be found in all walks of life, as farmers, tailors, seamstresses, factory hands, accountants, doctors, teachers, and small-business owners. Some families were wealthy; many more were poor. Many children ended their schooling early to work in a craft or trade; others looked forward to continuing their education at the university level

Even though “traditional religious practices and Yiddish culture played a less important part in their lives.” Central European Jews still held their religion to an important standard. In towns and cities across Europe (and in bigger cities in Eastern Europe as well) there were Jewish communities.

In Germany;

An organization unique to central Europe, the Gemeinde (community; pl., Gemeinden), served as a focal point of German Jewish life. Created to centralize local Jewish activities, the Gemeinde embraced all Jews within the country—including non-citizens. Gemeinden, which during the Weimar Republic became public corporations, were empowered by the government to organize local Jewish communal and ritual affairs. They hired rabbis and religious functionaries, maintained and built synagogues, and ran a variety of institutions, among them newspapers, social associations, libraries, health facilities, and charity funds. Tax revenues, collected either by the government on behalf of the Jews or by the community itself, supported communal activities.

Within the Gemeinden, Jews expressed communal identities in many ways: participation at the local level in youth movements, Zionist groups such as Brit Shalom, new Jewish schools, Jewish student fraternities, athletic societies, Jewish libraries, B’nai B’rith lodges, singing societies, the visual arts, and in Jewish museums.

This is only at the local level, this level of involvement also existed at the national level with national Jewish organizations in Germany.

In Antwerp; (I could not include the extent of the organizations but you should read here for the full extent of Antwerp’s Jewish organizations)

**In the late 1930’s there were in Antwerp twenty-two Jewish organizations and associations.

There were six professional Jewish organizations in Antwerp during the interwar period: among them Yiddisher Handverkerfarain was founded in 1919 and in 1938 merged with the Yiddisher Handerverkering (est. 1935); a painter’s association; and a shopkeepers’ association.

Sporting activity was promoted by three different clubs: Maccabi, the oldest, opened in 1920 and had sections for basket-ball, football, swimming, tennis, gymnastics, chess, and bridge. Hapoel belonged to Poale Sion-Tseire Sion party and opened in 1927 with sections for football, table tennis, and chess. The third club, Yask (Yiddisher Arbetersportklub – the Sport Club of the Jewish Workers) opened in 1935 and was affiliated to the Bund party. It included sections for football, tennis, chess, swimming and in addition it had a cultural section as well.

The first amateur theater circle started its activities in as early as 1878 and it was followed shortly by another group called De Vriedenkring. In 1912 the Yiddisher Progresiver Dramatisher Klub was founded. Antwerp was frequently toured by renowned Jewish musicians and performers as well as distinguished Jewish theater companies from other countries, like Habimah of Moscow, Die Wilner Truppe of Vilna, and Jiddisches Kunstthater of New York. Hatikwah was the first Jewish weekly in Belgium published in Antwerp by the Agudath Zion association in 1905 and until 1914 it appeared in German. During the first half of the 20th century more than fifty various Jewish periodicals, the majority in Yiddish and a few in Dutch, French, and Hebrew were published in Antwerp.** (sorry this won’t format correctly but all a quote from the linked source)

As you can see this community covers every aspect of life. From children’s schooling to sports to theater to Unions. The Jewish community throughout Europe was integrated into every facet of social life. Of course there are exceptions of some Jewish people not participating or being distant from these groups but for the most part the Jewish people had their own communities and organizations together. To “recant” their Jewish-ness would have been meaning uprooting their whole life. They would have to cut off communication with almost everyone in their lives, and move away from everything they had ever known. Of course, most Jews did not know the fate that was coming, so in many peoples eyes it was easier to abide by the new laws rather than give up their whole lives and recant their entire identity.

Sources: https://www.pbs.org/wgbh/pages/frontline/shtetl/reflections/ https://www.ushmm.org/outreach/en/article.php?ModuleId=10007689 https://www.bh.org.il/jewish-community-antwerp-belgium/

I think it's important to understand that the Germans didn't just run around and look for people with traditional "Jewish" features. They combed census, synagogue, and hospital records (among others) to figure out people's genealogies and how they related to the categories of the Nuremberg laws. They used fairly modern methods (punch-card computers) to do this, and had a state where documentation was necessary to get anything serious done. In the non-German areas they often had help from local authorities who would tell them who (and where) the Jewish people were.

So, of course, there were people who tried to develop false identities and "pass" as non-Jewish. But it was not the norm; an entire people cannot pretend they do not exist and have never existed in a modern world of records, documentation, and memories.

For a very strongly polemic but still interesting discussion of the use of records both prior to and during the Holocaust, see Edwin Black's IBM and the Holocaust. Black's essential thesis is that IBM machines were necessary for the Holocaust, and the polemic aspect comes from the fact that Black thinks that IBM the modern company should be considered in some way culpable (one can disagree on this). But it's a very interesting discussion of the role of record-keeping and technology. Much of the Holocaust was actually very "low-tech" (e.g., the slaughtering of villages in Poland with machine guns); this sort of thing was accomplished with the aid of local officials, who of course had their own records of who lived where, etc. It is also of note that there were several localities that made it difficult for the Nazis to do this job, by not cooperating with the Nazi demands for records.