I always find it amusing how many insults get thrown between the various nationalities. Personally, I find it hard to take those kinds of things seriously. At least in America, most of us get taught the old rhyme "Sticks and stones may break my bones, but internet tough guys will never hurt me.". As to the kind of rudeness that takes place on the servers, well, I have yet to find a server that is a rudeness free haven for the educated. Plenty of trolls on, regardless of where the server is located. Americans may have a lot of low-brow humor, or racism intended as humor, but it's pretty much the same in EU. Only difference is instead of faux-racism, you have actual dislike between various groups and nationalities. Only thing that seems to prevent ridiculous racist diatribes is that half the time the group that might want to start a big spiel wouldn't be able to communicate intelligibly to the people they want to insult.
As for australians, one of the few experiences I had playing over there was being kicked along with my friends after topping the scoreboards with 200 ping. This was following various insults of course. I have no idea how the average match between australians plays out.