HERE is the License Agreement which covers the teen rating. Look in section 5g.
HERE are the Rules of Conduct which clearly state
There are more, but I think those three cover it.
Bottom line is that it is completely up to EA/Mythic to determine whether or not the words in their game are abusive, vulgar, etc....
I've always been against the victim having to leave the area, or mute the abuser. It's a public chat, why should the people who follow the rules be forced out? It would be like someone in a public park shouting vulgarities and the police leaving him alone and making everyone else leave.
Great discussion though. I applaud all for not going too far to get it locked. Nice that everyone can stick to the issue.