I think it becomes a bit clearer if we take football out of it, because it removes some of the stereotypes.
We've all been on the motorway when somebody speeds past us. We've probably all gone a bit above speed limits but I'm talking the guy who roars past at 120 mph. We all know it goes on.
Imagine a pile up. Kids are involved.
Imagine the police don't divert traffic round but actually send more cars into it, to avoid the traffic jam further back.
Imagine they prevent emergency services from reaching the scene.
And then imagine they say "But drivers speed. It was that that caused the accident. They brought it on themselves by going far too fast."
They use those 120mph people to discredit everyone involved and to hide their own culpability.
In that situation, not one person would say 'but hey, they're right - people do speed. I've been on the motorway and seen people do it, my FIL was there when someone drove at 130mph, so maybe the police (senior officers) had a point to act the way they did!' You'd say 'Well hang on a minute, maybe there are people that drive at a ridiculous pace, but you still get an ambulance there ASAP, you still try to get people out of the cars.....'
And none of the other excuses would wash either (they'd been in the pub and tried to get there quick). It's because it was football and fans had the reputation of being little better than animals.
And I would dispute that anyway - I attended matches at Spurs from around 1985/86, when it was standing on the lower terraces. We went every home game without fail. I never saw violence, and I never felt unsafe. I have since had friends ask if I wasn't scared, because of all the fighting. Well, my folks wouldn't have taken me as a small child if it had been that bad, if serious fights were guaranteed at every game. It was bad, it did exist, and it was not pleasant, but it was not as bad as the media liked to portray. So I think this image of all fans as hooligans and all matches as excuses for riots was OTT and has a lot to answer for. (My mum went to a match where there was a streaker, and it got portrayed as a pitch invasion in the match report after. Really? One guy with his pride and joy on show is a pitch invasion???)