I steer clear of this too. The most offensive things I've ever said in Frontlines are "Who's ready to pretend to like PvP for 20 minutes" and "hey, if we pick one side to feed, we can end it faster". I can count on one hand the number of times I've even sworn, and I didn't today.
Another thing: the match finished less than 15 minutes before the GM pulled me in, so it had to have been something in chat, otherwise there was no way they could have caught it that fast. I'm starting to think they just didn't check at all, which is honestly just frightening.