Every devil needs his advocate, so.....
I encourage everyone to remember that there are two sides to every story. While there is certainly no excuse for police officers to behave in the manner that they were described to have behaved, there is also nothing to corroborate the gentleman's story either.
A traditional "he said / she said" scenario.
Indeed, he even contradicts himself in the story (or at least appears to based on the way the story is edited.) He describes himself as having "locked his camera in his scooter". Yet when he gets out of the police cruiser, not only is he no longer handcuffed, but has the camera right there in his hands.
He could be telling the god's honest truth, or he could be full of crap. Not enough here to go on to decide, and certainly not enough to indict the law enforcement profession as a bunch of "grade 12 graduates high on adrenaline".