It's because that is what he does. If someone is so obnoxiously rude about others, then I think it's fine to point out how ugly and obnoxious they are. I try to see the good in everyone, but when someone is just so outspoken and in such a rude way, they get what's coming to them.
I don't disagree, the man is a pig and much worse, but its still ironic to be blasting him for saying horrible things about someone when we are doing the same. It makes no difference what the reasons are, we are still doing the same thing (to a much lesser degree than him though).