This thread from /u/commiespaceinvader discusses Generalplan Ost, which is the larger planned campaign of murder in the East, beyond simply the Holocaust. It doesn't specifically address "why is it never talked about" in the way you might be wondering, but I would caution you about any question which is premised in that way, as the answer is rarely one that can be approached entirely objectively, as it, in reality, says more about where and when you were in school, and what kind of media you generally have been exposed to, so the answer can vary wildly for, say, someone with a basic high school education who graduated in 1960, and someone like this /u/Georgy_K_Zhukov guy who has read extensively about the Eastern Front of World War II. This answer I wrote a little while ago is not about Generalplan Ost, but it is about another topic on the Eastern Front, and I think is relevant for you here. The sum which carries over is that, while Generalplan Ost is a bigger deal than the Night Witches, it still is something which brief coverage - if any - is the best I would expect to see in a high school environment, and given how cursory education of even the Holocaust often is at that level (I'm failing to find it, but there have been some useful discussion chains between myself, /u/kugelfang52, and several others, about the poor quality of Holocaust education in the American school system, which perhaps he can remember the thread for), skipping over it is not at all surprising.

/u/Iphikrates already linked my previous answer related to this subject (thank you!) but there are some problems with your premise:

First of all, both the number of civilians killed in the USSR (7 million) and the number of killed Soviet POWs (3 million) include the number of Jewish victims that are also counted towards the approximately 6 million Jewish victims of the Holocaust. In this case they represent 1.3 million in case of the civilians and at least 50.000 (in case of the POWs) respectively.

Secondly, "objectively worse" is not a category that can be applied here, in my opinion. There is no scale of mass atrocity. Both the murder of millions of Jewish victims in Europe and the murder of millions of Soviet civilians and POWs (including the Jewish ones) are crimes that are just beyond imagination for us and any scale applied here about which was worse, is basically useless because it doesn't contribute in any meaningful way to our understanding of what these crimes meant or why they were carried out. Simply put, as I have written before, when you deal in the category of Nazi atrocities against all its victims "worse" is not really a category that can cover it anymore.

Thirdly, that the crimes of the Nazis against the population of the Soviet Union are not talked about is simply not the case in any meaningful sense. Various institutions charged with remembrance and research into the crimes of the Nazis deal quite extensively with the atrocities in the Soviet Union. E.g. the United States Holocaust Memorial Museum makes specific mention of the Soviet POWs in their Intro into the Holocaust and deals with both the Einsatzgruppen shootings, the hunger policy, and the crimes committed in the course of Partisan warfare extensively in their exhibition.

Similarly, both German and English language academia has produced a wealth of books that could fill whole libraries about the crimes committed by the Germans against the Soviet populace. This goes as far back as the late 70s with Helmtuh Krausnick's publication about the Einsatzgruppen but also includes Christian Streit's Keine Kameraden, which is still the definitive book about the crimes committed against the Soviet POWs but also more recent publications such as Omer Bartov's books about the Wehrmacht in the Soviet Union. Crimes against the Soviet populace even took center stage in one of the most hard-fought historiographical debates in recent German memory in the form of the so-called "war of annihilation" debate.

In 1991 various German scholars put together the so-called Wehrmacht exhibition, which premiered in 1995. It dealt with the various criminal activities of the Wehrmacht and thus focused mainly on the Soviet Union. Not only was this exhibition seen by thousands upon thousands of people in subsequent years, it also sparked a debate among German and also English language historians, namely, did the Wehrmacht set out with plans for annihilator warfare into their war in the USSR or was this something that arose from the situational circumstances of the war. Historians such as Manfred Messerschmidt and also the aforementioned Omer Bartov posited that the Wehrmacht was fighting a "partisan war without partisans", meaning that they employed brutal and ruthless policy against Soviet civilians, regardless if they were involved in partisan warfare or not, simply because they were Soviets. And while this did receive some backlash, mostly from conservative historians, by now, this has become a pretty accepted model with which to explain the German crimes in the Soviet Union – as motivated by racism, hatred and Nazi ideology.

Additionally, it ought to be kept in mind that virtually all of the scholarship produced in the former Eastern Bloc during the period of existing socialism (and some of that is still surprisingly useful and therefore read today) placed a strong emphasis on the plight of the Soviet people – to such a degree in fact that other victim groups unrelated to socialist political activity were left out or subsumed in official political memory of the Nazi crimes: Within this nexus of memory, places like Belzec, Treblinka and Sobibor were not remembered as places where people were killed because the Nazis persecuted them for being Jewish but places of socialist Soviet suffering. This was a problem within itself from a historiogrpahical standpoint (and a political one seeing the continuation of such trends under new auspices today in many formerly socialist countries) but it goes to show that there was and is a lot of research and dealings with Nazi crimes against the Soviet populace.

While I can't address the American school curriculum and its probable shortcomings (where I suspect there are many concerning WWII and the Holocaust), as I've said, there are various institutions out there who make the effort to deal with German crimes against the Soviet Union and its populace and there is far from a dearth of information out there – rather the opposite.

For more information, I'd suggest the following books among others:

• Omer Bartov: The Eastern Front, 1941–45 : German Troops and the Barbarisation of Warfare, 2001.

• Richard Evans: The Third Reich at War.

• Waidman Beorn: Marching into Darkness (Beorn did an AMA with us here)

• Edward B. Westerman: Hitler's police battalions.

• Stephen G. Fritz: Ostkrieg: Hitler's War of Extermination in the East, 2011.

• Jürgen Förster: "The Wehrmacht and the War of Extermination Against the Soviet Union".

• Alex J. Kay: Exploitation, Resettlement, Mass Murder: Political And Economic Planning for German Occupation Policy in the Soviet Union, 1940-1941. 2011.

• Lee Baker: The Second World War on the Eastern Front.

• Ben Shepherd: Hitler's Soldiers: The German Army in the Third Reich.

• Mark Mazower: Hitler's Empire.

• Dieter Pohl: Die Herrschaft der Wehrmacht in der Sowjet Union.

• Christian Gerlach: Kalkulierte Morde.

Related to your question, you might be interested in this earlier answer by u/commiespaceinvader, which doesn't specifically focus on Soviet civilians, but does explain why there's a tendency to highlight the fate of the Jews in particular.

It is also worth pointing out that the traditional, Soviet portrayal of German crimes during WWII was to focus on crimes against all civilians, downplaying the particular suffering of Jews (what we would today refer to as the Holocaust) by calling victims “peaceful soviet citizens” or “peaceful soviet residents”. This trend of subsuming Jewish suffering into a wider story of people who died in bombings, as a result of German reprisal killings in response to partisan activity, from illness, or as part of other campaigns of German violence (which did exist, and were directed against so-called “gypsies”, the mentally ill, Communists, etc) began in 1943 and continued until the mid-nineteen-eighties, when Gorbachev came to power and glastnost’ began. So OP, when your parents were young, if they were growing up in the USSR, they would have heard no public discussions of Jewish suffering, and only broader descriptions of German crimes against the Soviet people as a whole.

It is important to remember that the way we commemorate and remember events today is not necessarily the way it has always been.