It's obviously not all of them. It can't be, because the situation is more nuances. You have a design which forces even PvEers to have to play antagonist. so I don't believe all people playing Antagonists are, in fact, people who enjoy causing misery to others. I realize many people are there because they HAVE to be. And, to be honest, I don't believe LordDraco is interested in causing misery or trolling ("unless it's me"), but there are people who ONLY play antag who've stated they don't care if the raiders are noobs, they, in fact, like this. This is a universally understood attitude in gaming in general, PvPers generally are micro-sociopaths. Sure, you get you're "honorable" PvPers who want a fair fight, but this is the exception not the rule.
Also I'd like to state the horrible situation from the other side. We had an antagonist the other day that was level 6. Our group was all 50+. We won, but it was horrible, why is he fighting us? He kept trying but he just didn't do enough damage to us, and we would WASTE him with firepower in moments. It was an unpleasant feeling when we won, and let's face it, we were going to win no matter what. For the reasons stated above I think PvP HAS to be an optional thing, or at least more well mitigated with barriers and filters that prevent this sort of thing.