Unfortunately I've been that really bad player before. It seems like it always takes me a while to get my barrings straight in a new dungeon because I don't want to rush ahead. Hell, I never even knew how to mark mobs before lvl 45. That was when someone politely taught me how. Most of my duty finder parties have been good and patient, but remember that instead of calling someone a 'noob' or worse, you could try teaching. I certainly appreciated it.

In any case, SE's policies are pretty clear regarding this game. If you're a douche, you're liable to get reported and potentially banned. And as a community, if we see it going on, we should step in and let them know it's not welcome. We reap what we sow. And remember that the freedom of speech is not the 'freedom to speak without consequence'.