​Hitler was a Vegetarian.

I once knew a vegan who
​
​wasn't very nice.

This is a lie. Hitler ate meat and animal products. So he was a long way from being a Vegan.  - https://www.adaptt.org/veganism/hitler-and-vegetarianism-both-are-evil.html

​Just because one Vegan wasn't very nice doesn't mean that the Vegan philosophy and lifestyle is not a good thing to follow. There are many non-vegans who are not very nice too.