I have found the opposite. I find this game has some of the most mature servers and core group of players than any other FPS game I've ever played.
I think when there is a deliberate TK'er here it stands out more however, and more attention is drawn to it because the abusive/immature player/TK'ers are not generally a regular part of this game. In other games it's so common that it goes unnoticed and nobody pays attention to the constant messages coming up slinging abuse all over the place and the "WTF" every time a TK happens.
In RO accidental TK's happen a lot more often than other games, most TK's are accidents and most players realize that and are forgiving. You said 50 to 70 percent of the games you join have some sort of TK'er. Well, I'd say it's 100 percent of the rounds/servers you join, you will see TK's and again, 95 percent of them will be accidental, just part of the gameplay in a game like this.
It's the immature players who make a big deal out of every TK and the equally immature players who TK in "revenge" or just plain act like idiots and TK all over the place, talk abusively and generally act like kids (even though they may be 25). Luckily in RO, there are a LOT less of those immature players compared to other games.