A 2 month+ mafia ban seems kinda silly honestly. If worstgen had a system similar to what OLF does with ranked and unranked then yeah I get it. Good way to stop any constant hostility and good initiative not to take it to far or else it effects your ranking if your into the competitiveness of Mafia games but from what I see worstgen games are usually games just for fun. How you play in one game doesn't effect your score in another game.
Now I also under stand hosts tend to be passive when it comes to players who take things personal with another player and alot of times hosts either don't want to mess up their game by mod killing or replacing a player or not get involved to not show any bias. But I also believe hosts are within their rights to not get that heavily involved because at the end of the day they understand these games can get heated, people will say or do things in the moment. Theirs a reason the post-game exists, and I encourage the hosts to encourage their players to let out their grievances then and there rather it be about the game itself, the host or another player.
Let them get it out of their system and if it's still continues outside the game thread ala here or another game, instead of banning them outright from playing why not just ban the 2 parties from playing a game together for a game or two if they aren't willing to either drop it or ignore each other. Dunno my 2 cents