I'm fairly sure thats the job of the moderator in the forums, and is not automatically censored (may be wrong).
Plus, the forums can be filtered by the javascript, and I think the in game chat box uses a different, more complicated type of script (though again I'm not sure).
I quit the game because at 2 up on hole 13, my partner (the abusive one) decided that it would be funny to start messing up each shot purposely (i.e., aimed a 5 foot birdie putt 50 feet in the opposite direction, used his putter for his drive on 14, and used his 5 iron whilst on the green on the same hole to hit it 150 yards back down the fairway whilst saying "you won't win another hole" ... it gets rather pointless playing then (and anyway, shortly after leaving, me and one of the others from the original game (another master) got invited into an A/S with two legends, which was fairly good!)
Yes, the response, or lack thereof, really got me too...a little odd, I had sent 8 screenshots, and whats their advice? Take a screenshot, lol
Edit: Actually you were right, it does automatically censor some swear words (cuss words) but if you add "ety" to the end of the F word, it allows it...lol