You can't prevent bashing from happening (because what's an objective opinion to one person is a subjective insult to the next), but how about creating a place where people who actually like tennis (given the general tone of most of the posts currently in GM, I'd say it's a minority and most come to MTF to argue) a room to do so without having to wade through the trolls, the flame wars,...
There could be one section where matches are being discussed (tournaments, matches, calendar issues, rule changes,...).
--> In this section, I'd suggest people to call the players by their names (instead of the nicknames such as Fakervic, Frauderer, Nadull,...) and actually make an effort to value the players instead of just throwing insults to see what sticks.
This would allow more freedom in the other section with general tennis discussions (with topics such as the GOAT debates, comparing of eras, various "what if" scenarios, funny pictures, videos,...)...
---> this section would be given more freedom, allowing more space for arguments, nicknames, etc.
I would put the current "off topic" sub-section, that now exists within General Messages, there.
All in all, General Messages would have 2 main areas:
- The Match Area (allowing doubles matches to go in there as well): strict moderation
- The General Area: not so strict moderation.