In my opinion, and mine alone, the ban is very well deserved (assuming I'm reading right and there was a ban). I don't think it's worth getting rid of FM over, I certainly don't want that, but if this weren't FM, if it were just some random guy, we'd all be behind even a permaban. There's absolutely no excuse for any of his multiaccounting. When he plays himself, he is benefiting himself with no competition, even if he "played fairly both sides", he still gets shards and experience points on both accounts which he didn't really earn. And when he's playing against other people with both accounts, even if he thinks he's using each equally, I'm not under the impression he told the other players at all. There will always be a bias there to attack other players more and to pull the punches against your own accounts at the very least.
Don't misinterpret me, I support having second accounts in the game, I know Autumn uses second accounts often to track the lobby while he plays, and that Highlander uses one to play without being targeted for his rating. That's completely understandable. But FM's case was very different and I sincerely hope he's learned his lesson.