I mean....I don't want to be the guy to say European culture was the problem, but there were German concentration camps when Adolf was just 16 years old and British concentration camps before even that. Additionally Hitler wasn't responsible for eugenics, that was just Western European science originating in....the 1800's I believe? I mean scientists were literally publishing books on how the poor and the disabled were destroying society, and eugenics continued for a short while after the end of WW2 (until very recently as well if you include Israel and what's being done to people in detention camps at the border in America). Killing baby Hitler doesn't stop the psychopathy. Apparently the Nazis were huge fans of Ukraine because they were impressed with how dedicated the Ukrainians were to killing (Poles? Jewish people?). Balfour for example aided in the creation of Israel not out of a love for Jewish people, but because he was a rabid antisemite who wanted to remove Jewish people from Europe. Churchill actually admired Hitler and sent a letter telling him he actually agrees with him.

Basically Stalin shouldn't have stopped at Berlin.