To say that there have been some unbelievable responses would be suggesting that the responses from a couple of the forum trolls were unexpected. Unfortunately they were entirely predictable, although the addition of playground reponses - "no grassing" - was a more surprising but equally thoughtless comment.
The problem with confronting idiots at matches is that they respond idiotically. I was with a group of friends on the East Stand benches at The Dell. We were all getting hacked off with two homophobic guys in front of us and one of our number, DM, objected rather more loudly to their drip of unpleasant comments. The guy turned round and hit him in the face, and there was a danger that our mate would have been thrown out along with the offenders. We reported the matter to the stewards and at some subsequent games they had a camera and microphone trained on these guys. Fortunately we moved to SMS soon after as these two were consistently unpleasant and stupid.