Good satire, but the boring facts were that an alocholic old troublemaker with a heart condition had been delibertaley baiting the police by strutting up-and-down in front of them, taking the piss.
A not-very-professional policeman, who may well have been a bit of a natural bully, lost it and belted him, as I am ashamed to say I might have bene tempted to do as well - but I am not a trained professional who is expected to be able to keep his cool when troublemakers try to wind him up.
Very unfortunatley the old twat died, but there is no reason to believe that the policeman (who would not have known that he was an alcoholic or that he had a heart condition) intended to kill or even injure him. Certainly the policeman should have been disciplined and/or sacked, but there has been a lot of mischief-making by the anti-police lobby trying to make this sound like a case where the police deliberately and sytematically chose to beat a completely innocent man to death. Hardly what happened here! If you or I had been struck like that, we would have screamed "ouch" but been bright enough to take the hint and limp away brikly to leave the police to do the job they were there for.
Unluckily for the policeman he was hung out to dry by his employers who were happy to make him a sacrificial victim in their attempt to appear, for political reasons, to be a completely benign, 'always-on-the-side-of-the-poor-and-downtrodden-proletariat' force.