We don’t ban for Linux usage. We ban for hack usage. I’d wager any investigations into the accounts of anybody who claims to be banned for use of Linux would reveal they were actually using unauthorized programs - unless there’s some kind of error with the cheat detection system. If that happens, we’ll clear it up in customer support upon appeal.
If you can run the game on Linux, more power to you, we just won’t help if the game crashes. If you’re ever in doubt about an account action, you’re always welcome to submit an appeal. For some insight however, of all of the times I’ve ever seen a claim of “I was banned for [insert innocuous program here],” it was actually a cheat program. Doesn’t mean the system is flawless, but we’re usually pretty confident in what we do and if we mess up we’ll make it right.