Hitler followed a vegetarian diet, not a vegan diet. He was also prescribed a meat-free diet by his doctor and it was useful for his public image to show himself as loving animals, so it’s highly debated how much of it might have been from some genuine moral conviction. Not least, because it would make no fucking sense when he’s slaughtering people in the millions at the same time. en.wikipedia.org/…/Adolf_Hitler_and_vegetarianism