Well, if s/he actually runs an exit node, then there is something, as the users actual home IP address is blocked. I still wouldn't call it a ban though. Bans are on people, not on IP addresses.
It's an unfortunate situation but there is nothing we can do about it. Perhaps there is some way Tor could mark packets coming from an exit node as having been forwarded so we could somehow tell the difference between Tor packets and packets coming from the exit node itself. Doesn't sound likely to happen, though (and would make blocked Tor all too easy, so I doubt the Tor people would go for it).