It is a private Club. City can set whatever rules it likes. They can issue bans as they see fit. They do not need to go to Court.
Well they can't as it happens. Football Banning Orders are covered by law and statute (Football Spectators Act 1989) and there are requirements that have to be met when applying for one. They also have to be signed off by a court I believe, so at least a magistrate.
The requirements are somewhat wide though, so you could get a football banning order even if you go to the pub the day after a game, get into an arguments with some rags and it turns violent. You can be banned for the crime of associating with known hooligans so if you're in the pub with a mate, and a mate of your mate comes to sit with you and spends the rest of the evening chatting, if he's a "known hooligan" you could in theory get a banning order even if you had no idea who he was or his past.
I know of a case where a female City fan got a banning order simply because she appeared on a photo with Rod Rhoden and his mates (long after his hooligan career ended) that was used on the cover of his book. She either just got dragged in or was with a lad who knew some of the others.
I didn't think you could get a banning order if you'd not been charged and only issued with a caution however, but that may just be if the police want the banning order. City may be able to apply for one regardless and, on the face of it, this case meets the key criteria of being (a) football related and (b) '...using threatening, abusive or insulting words or behaviour or disorderly behaviour'. Obviously kippx kid disputes he was guilty of (b) in relation to "abusive or insulting words" but jibbing in probably counts as "disorderly behaviour".
Clearly he's been a bit of a dick but that doesn't mean he should face being banned for 3 years or whatever. The criminalisation of football fans is ridiculous. Would you be banned from public transport for 3 years if you were caught without a ticket on a bus, train or tram? You'd get a fine probably and that would be it.