Insults in chat, teamspeak or forums are not allowed. In any case, the offender should be warned, kicked if they continue, and banned if they continue after that. If they get unbanned and start at it again, permaban them.
Admins aren't here to babysit. We are here to make sure players abide by rules and to get rid of the ones who don't, while trying to enjoy the game ourselves. Anyone that has a problem with that will most likely follow suit with the ones who don't wanna listen, and will probably end up banned at some point as well.
Easy thing to do, if you see someone breaking any of the rules intentionally, tell an admin or take screens and post them in the ban section and get the baddies punished. If you broke a rule and were corrected or punished by an admin, don't argue with them as it makes it worse on you. Accept the punishment or appeal it in a reasonable manner, but don't argue your case in game over chat or teamspeak.
Do I care if you hate me? Do you wanna know the truth?
C'est la vie, adios, good riddance, f*** you.