The police have to be careful with regards to ‘wading in’. All of that is on CCTV and the police can’t be seen to be kicking the shit out of someone, even if it is a Stoke fan.
From my East Stand vantage point it looked as though the stewards were slightly heavy handed shoving him down the stairs, but he wasn’t going to leave quietly and when he tried to scurry off down a row the steward rightfully grabbed him only to be set upon by several Stoke fans. I expect nothing different from them.