With regards to being worried about being banned by FD for language I think it's a lot of smoke with no fire here. With a bit of common sense, which FD would use when analysing these complaints, it should be easy to avoid any issues. If someone swears at you in game then essentially they threw the first stone and also, by using swear words have indicated they find that language acceptable. So swear away, FD would see the full chat log if they did report you. If someone tells you to expletive off out of the blue, then yes, that would be a problem for them.
Also, it's easy to be insulting without using swear words, often in more extreme ways than swearing. If they bait you into swearing at them and then report you it's pretty safe to say that you won't be the one facing any issues as they'll see what caused it.
Obviously homophobic and racist hate speech are a different thing and if they're using them freely then they've got more personal social problems to worry about fixing than playing this game.
It's all about context basically and most adults should understand the boundaries of that by default. There's also a big difference between swearing in general conversation and actually hurling abuse at someone, swear words or not.