The question in the title is detached from the one in the description. The Nazi movement as a political force and the Holocaust are two different things.

Hitler's biography is long, intricate, complicated and we often have contradictory claims. Hitler's friend during the 1900s and early 1910s for example, August Kubizek, has been a rather controversial witness to say the least.

Kubizek asserted in his 1953 memoir about his friendship with Hitler that the eventual Führer already had been antisemitic during this time. That is by all other accounts false - Hitler for example had found friends in several Jewish individuals during his time of poverty in Vienna after 1909.

However, Austro-Hungarian society was at that point already deeply antisemitic and German Austrians were divided among two camps: The loyalists and the nationalists, with the loyalists supporting the Habsburg crown and the continued existance of the Austrian union with the other Danube peoples, whereas the nationalists, driven forward by German national liberalism, rejected Austria-Hungary and instead sought to unite "German Austria", that is contemporary Austria, South Tyrol, the Sudetenland and other German-speaking areas with the German Empire while leaving the rest of the Habsburg Domain to its own local politics.

Hitler at this point could already be attributed as a nationalist in this Austrian sense, but he was at the time far more socially liberal than he would end up being. Wilhelm J Wagner attributes to Hitler the quote Jeder war mal ein Sozialdemokrat - 'everyone was at one point a social democrat'. He said this in his early days in the Nazi movement without a specific reference point, but likely to cover for himself that he worked at one point with the Bavarian Soviet Republic, carrying the red armband of the communists.

That was of course after World War 1, the conflict that really shaped Hitler as a person. Kershaw identifies it as the chief cause for him to make his move into the political arena. Hitler during this time undergoes several key changes to his political outlook on the world - he ditches Wilhelm II from his ideology and becomes a committed anti-monarchist for example.

And he gets in contact with antisemitism. As an Austro-German nationalist, antisemitism would have been a natural pickup for him before the war, with people like musician Richard Wagner, an idol of Hitler's, as well as Austro-Hungarian politicians like Georg Ritter von Schönerer, Georg Jörg Adolf Josef Lanz von Liebenfels and Karl Lueger all being influential faces in this late 1800s / early 1900s Austro-Hungarian antisemitism. Liebenfels particularly advocated the 'planned breeding' (Planmäßige Reinzucht) of a 'heroic noble race* ('Heroische Edelrasse'). Proving definitively that Hitler came in contact with these early thinkers is difficult, but each of them served as example to later German and Austrian antisemitic hatred and Karl Lueger specifically, the mayor of Vienna, used regularly a term that founds its way into Nazi ideology and is still in use by Neo Nazis to this day: Judenfrage. The 'Jewish Question'. In Germany itself, thinkers like Alfred Ploetz and Alexander Tille became forward thinkers of German-style social darwinism. Tille asserted in his philosophy that the socially incapable have no right to life and that a race too weak to defend itself from another race forfeits its privilege to exist.

So, back to Hitler being a man without perspective after the army he fought in just lost a world war. He stayed in the armed forces, particularly in Bavaria, where after a short romance with the Bavarian Soviets he switched sides to the "Whites" that cleaned up the BSR and got re-engaged his position as a spy, coming into contact with a political party called the DAP. This "German Workers' Party" finds Hitler's sympathy, as it is built primarily around antisemitism as a political platform. This is something that would go into Hitler's political identity as well: Never was the Nazi party primarily about economic plans or taxation reform, never was it primarily concerned with Versailles Treaty renegotiations or any other tangible policy point - it was built around the fundamental thesis of a Jewish inferiority to the Nordic/Master/Aryan/German race (these terms were used interchangably). The entire premise of the Nazis was an appeal to emotion rather than sticking to provable facts, which is rightfully classified as a logical fallacy in contemporary debate rules.

So after Hitler got permission from his commanding officer to join the party - he claimed it was to better subvert it - he quickly rose to prominence as a good orator and emotional speaker (again, the emotion thing). He hijacked the party and rebranded it from DAP to NSDAP, National Socialist German Workers Party.

My point to his entire thing I wrote so far is that antisemitism was a deep-rooted issue of German nationalism during the 19th Century. Hitler did not create antisemitic hatred, he perfected the formula. As per having him die and seeing if that prevents the Holocaust? We have good reason to believe that the true architects of the Holocaust sat behind Hitler's throne in the shape of Heydrich and Himmler - Hitler didn't just come up with this novel idea of killing everybody he didn't like; it was instead deeply rooted in the ideology of people like Liebenfels and Lueger and had plenty of supporters on the ideological fringes of the far right. And the Nazis had good speakers other than Hitler, like Goebbels. They had influential writers like Rosenberg and Streicher. Although Hitler's part in the guilt for the Holocaust in our timeline is immense (and, yes, it was), we have no reason to believe that a Nazi movement without him wouldn't have gone down the same path. His actions were a symptom of a century of anti-Jewish hatred, not the beginning of a decade of persecution.

Maybe the Nazi Party wouldn't have been called NSDAP and maybe it wouldn't have risen to power - but we can't just make a blanket statement assigning all guilt of German society onto the person of Hitler. That is a postwar construction by German and western Allied historians that overcompensated for the mistakes made after World War 1 by making sure to make absolutely clear that Germany as a collective didn't carry an elevated guilt for World War 2 as had been asserted in Versailles for World War 1. That is where the tendency to deflect blame to the Nazi higher-ups - and conveniently mostly those already dead or executed for war crimes - instead of seeking the root of the problem with German society at large. That said, would the average German person of 1932 have approved the industrialized genocide of eleven million individuals? There is no reason to believe that.

It's a fascinating question though, isn't it?