A chat filter wouldn't stop the rape though, only limit the players on how they're able to communicate with each other.
There is indeed quite some bad language in the chats but I'd actually suggest taking screenshots and report it to us here on the forum, it will be dealt with.
This filter thing has been mentioned in some other threads in the past.
From seeing the discussion but also my own point of view, adding a chat filter wouldn't stop bad behavior in the chats, it would also limit the players of how they could use the chats if there were to be an "effective" filter, if there just were a simple filter people would find their ways around it rather quickly, in some cases people would probably think it's ok to swear just because the filter is there as well and that's certainly not how it should be.
Bad fishes get caught though.
