I personally don't find Theo to be rude to newbies. I myself am green behind the ears, but have been replied to by Theo in a more than courteous manner. In short, if you put yourself across as an idiot, you'll be treated as one, newbie or not.
I get the impression that most of it comes down to egos. Those with the bruised egos tend to become Theo's critics. Be respectful and you will find the respect returned. Attack Theo or OpenBSD and you'll be retaliated against. It's not Theo's problem that he counter punches like he does.