I once was on the "shit on the villa" roll call in a Birmingham City fanzine, i didn't pay the £2 myself for the honour though.
Never got one bit of shit for wearing City stuff from any fans of any of the clubs in those days around the City, thing had mellowed out by the early 90s, but was amazed by how many Brummie Man Utd and Liverpool fans there were.
Plenty of fans act like dickheads on cup final day, and I experienced something similar after the 2011 cup final at a service station and had an episode with a middle aged stoke fan who was similar to the guy in question. Paranoid as fuck afterwards though. God knows what the Villa fan went through after this, he will be finding out hard to live with himself no doubt , glad they caught him and did him, it will be some solace for the kid and kid family, If the father had seen him at took action, no doubt he would have been in front of the beak too. "Taking the law into ones own hands is an aggravating not a mitigating factor" you are fucked whatever you do.