In my experience, the rudeness gets worse as the ratings get higher, unfortunately.
The higher up the ladder you climb, the more seriously players tend to take the game - and, as a result: the angrier they get when they lose. (Or, the more spiteful they get, when they win.)
These days, I keep my chat disabled by default. Chess is for chess. If I want to chat with other players, well ... that's what the forums are for.
I have the same feeling that its worse at the higher levels. There are even titled players who spam a draw after every move when they are down a rook for nothing.
Probably not real titles.
Playing about with blitz, I've noticed a few strange comments down at the 1300 level. I've realised I don't like online blitz as a competitive game but it's great to use to mess around with because you get a big variety of approaches to the game.