Don't really understand how the police attitude to which you refer (which I didn't see, despite being at the front of the kettle myself@) could explain a) smashing up toilets and seats (well before the kettling), or indeed b) pulling off wing mirrors and abusing locals. So the police are...
This -- at the last away match at Selhurst, I didn't like being kettled after the match, but equally I didn't like (and was embarrassed by, frankly) watching some of my fellow Albion "fans" ripping out seats, damaging toilets, vandalising large numbers of cars, persistently rushing the police...