As people point out the police face violence every day in their jobs, and arrest violent criminals on the regs.
They mostly do it without stamping on people.
Like literally every day, maybe even every hour there's a copper somewhere, wrestling some scumbag to the ground and putting themselves in danger. And not stamping on anyone.
Kicking and stamping (and later spraying the people against the wall, interesting it was all the same guy, was he still riding the wave then?) is the story. Police doing normal police things, scumbags doing normal scumbag things, isn't a story, it's a daily occurrence.
I get some people don't care what happened to the guy on the floor and I feel little sympathy for anyone that fights and then gets a kicking. My issues are with a highly trained armed policeman that apparently gets a bit extra and emotional in dispensing what is unfortunately a likely part of his daily duties. Poor split second judgement and a gun sounds like a worrying combination.