Even before the match folk were talking about running on the pitch as if it was allowed, so I feel like Meldrew could have been any one of us in the giddiness of the moment. I bet that Blue dad whose daughter was pole dancing on the broken crossbar will be feeling a bit nervous right now.
A previous job took me to a lot of courts and the problem for defendants is while there are guidelines, how an individual case is dealt with it totally subjective, to the point what happens to a defendant really can depend on what mood the magistrate/judge is in, whether or not he's had lunch etc.
From what I've observed magistrates can sometimes be harder to persuade than crown court judges because they are lay people and rely on the legal advisor to tell them what to do, and the power can go to the legal advisors' heads.
Meanwhile even if you get a district judge in the mags they might be on a power trip. Then there's the scapegoat effect - the magistrates know there are concerns with coked up, boozed up disorder at matches - and end up making an example of whoever crosses their path even if the individual circs are minor.
I don't blame the OP for trying to represent himself, the problem is, even if a lawyer makes the same argument, their voice carries more weight and shows respect for the process. Plus many defence solicitors are football fans who like to stick it to the man (generally Alty Rags but still) so they will generally have a go for you.
As others have said it does help to have representation, and if possible an older relative/partner who looks respectable and contrite to go along with you. Anyway, hindsight is wonderful thing... hope you can appeal your ban Meldrew.