While obviously not everyone wants to see people swearing constantly in the lobby, this is an M rated game, and NPCs get to swear all they like. Hell, Afin says a few right in the tutorial. So isn't it a bit silly that players aren't allowed to say ANY "inappropriate" words at all? Simply dropping a "Filter Profanity In Chat" option in the menu should be fine for everyone, yeah?
Apologies if one exists already and I'm just blind, but I couldn't find anything when I looked.