My twopenn'orth: I try to limit my mockery to those 'Catters who have shown they can take it in the spirit it's meant and who respond in kind. I don't criticise other's right to opinions, but don't care if they criticise mine! Don't mind name-calling (sticks and stones...). Don't get involved in religion/politics/ medical threads as I don't think my views are appropriate on a music site. Some thread starters seem in a fragile state and are easily offended by sharp responses. Sometimes I read the opening thread and feel like saying "Pass the sick-bag" but hold back. I've stopped criticising obvious "stirring" anonymous threads, just don't rise to the bait, let 'em die. And I'm sorry about all the old jokes (I lied, I'm NOT!)
None of the above is meant to be a guideline to anyone else, just my way of drawing my own line.
As the Mudcat is "us" and we are all individuals we can all choose our own parameters. (God, I sound pompous!). If anyone really asked my advice I would say: If a thread offendeth thee, then read it not, nor respond to it. For verily, thy silence will kill it off (First book of Skiffler verses 1-2).
When in doubt think "Hey, lighten up, guys, let's sing a song.
RtS ("Nobody loves me, everybody hates me , think I'll go and eat worms" as we sang in the Wolf Cubs [Cub scouts])