I think being arrogant, trolling or as you put it "a dick" has nothing to do with new/old but that individual's personality. If I could generalize most "dicks" I've met in the game are usually a lot worse than they think they are. Also I have experienced new players being rude as well.
That said I believe a newcomer will learn more if he does endless 2's than joining a bg. The less parameters that influence the outcome, the safer it is to draw conclusions as to what is wrong when you lose.