People don't seem to understand it doesn't matter what happened in the lead up.
That is pretty much the key thing.
Given the police are allowed to use "reasonable force", and once someone is down you can't keep kicking them as that's not "reasonable" and if the officer doing the shoeing then moved on to attack another person
without ensuring the person they've just stomped is secure then they've not even got the defence of "I was restraining the suspect" as they didn't complete the restraint.
At the very least the officer is likely to get any firearms certification he's got for the force revoked because they are meant to justify every single round, or even just pulling their weapon, and if they can't be trusted to deal with something that hasn't reached the level of "potentially lethal force justified" they can't be trusted with having the option of lethal force.
I always wonder what the public backlash would be if the lad who got booted in the face was a typical council estate chav in a kappa tracksuit.
I doubt it would even warrant a post on reddit, nevermind national news.
Oddly enough for me it wouldn't matter if the guy being stomped was white, black, or pink with yellow spots*, was dressed smartly, casually or in rags.
*Well maybe in that instance, we all know Mr Blobby was a creature from another dimension sent to test the sanity of the UK population, and liked to slow roast anyone without the right ward who got lost in Crinkley Bottom.