How is PETA crazy? I hardly know anything about it, except that it seems to be belittled by people because it's considered a "liberal" organization. If you are going to list examples of particular members who have said or done questionable things, don't bother; that doesn't answer my question.
I think people who take (and act on) extreme views cause more problems than they solve. People start to hate them, and, by extension, their cause. And that bugs me, because a few PETA members acting on extreme views can ruin it for others who try and protect the rights of animals.
For example, when I told somebody that I had become vegan, they said "you aren't going to throw paint on me when I eat meat, are you?" -- they were obviously joking, but there's a seed of distrust there. They distrust me because I've taken a view that is shared by extremists.
As a result of that type of stereotype, I generally refer to myself as crazy in those situations. It's a lot easier to cut off that argument early by making it into a joke. "I'm a vegan.. yeah, I'm probably crazy, but being crazy can be fun too!" -- it may belittle my beliefs a bit, but it's better than somebody thinking it to themselves.
That's just my 2 cents from what I've seen in the media and experienced myself.