IMO, I think there are 2 reasons for the escalation in rudeness lately:
1) More competitiveness. People are out for blood because more people are starting to think of online poker as a source of income and less for fun.
2) Sad to say but I believe more underage players are bringing the maturity level down. Judging by the spelling and grammar of most insults I see, the 12-14 year-old middle-school crowd is catching on to online poker.
I used to be guilty of #1 (see Stick's Poker Blog
: ...And I'm a Name-Caller-Aholic ). But now I'm pretty much cured, though I do like to drop in some sarcasm from time to time. "Q4 is good but 72 is better." "What a great player!! You should go pro!" I know I shouldn't, but I'm weening myself.