Currently, there is no word filter nor muting options. I guess you could suggest it, but is it really needed that much? I often don't give a *BEEP!* about what other players might call me in games. Instead, I mark them as prioritary targets.

Look at it this way, if he calls you a niggar and you beat him, it will be doubly humillating for him.

Just put things hard for him in games.
And welcome to the MULE jungle.