Unless he was hacking, glitching, or exploiting, you have no rights to your claim provided you perma-banned him (wasn't it only for five minutes?).

If the guy is honestly still being a menace to the server then you should ban him based on the appropriate punishment. A perma ban is not appropriate for anything other than hacking, certain glitching, and certain exploits unless the clan members decide on it. (NYS I believe can back me up on this considering I have seen him say this a couple times, if not then I will retract that last statement).

Autumn was in huge trouble for doing the same thing with Walter (granted Walter wasn't as bad as Chibby) and I believe her admin was taken away as a result.

Also why aren't YOU taking issue with the demo if you saw it? I normally don't view demos and therfore I don't have much opinion to vote on the merit of the claim that the person was in fact hacking. However in this thread I have enough information to know that he did not deserve a perma ban (based on the fact you admitted you banned him for his actions while having admin, none of those being on the list of offenses that require a permanent ban) in this case.

In fact, the sentence after what you quoted is the most important here:

III. Perma bans
This is the highest punishment a player can receive. It can only be granted by a relatively small number of Upper Level Admins. Perma bans usually require a demo but always require that the player in question, beyond a reasonable doubt, committed an offense against the server and or community. Like any ban these can be applied but require a 2/3 majority vote from ALL upper level admins. If the ban appeal is denied it can NEVER be made again.
You didn't abuse, so don't think I believe you are an admin abuser. It just seems from the facts provided the wrong punishment was handed out.