One of the terrible things about being vegan are the arguments that your omnivorous peers always want to start. The most useless (and wrong) point they usually bring up is the "Hitler was a vegetarian" argument. First of all, Hitler was not a vegetarian, and I'm not sure why that rumor started. Second, and more importantly, what does it matter? Who would care if Hitler was a vegetarian?
It isn't just vegetarianism that the Hitler comparison is used for. How many times has George Bush been compared to Hitler? I'm not saying there's no comparison, but what I do want to get across is that using Hitler for comparison is just a form of fear-mongering. And it degrades every discussion it's used in. When I'm debating with someone and they say something like, "Well, that's what Hitler did", I completely dismiss their entire argument from that point on.
If you're argument is so weak that you have to use Hitler, just stop arguing. It's time to do some research.