I watched a video of this incident last night, absolutely horrified by the brutal, sustained beat-down.
This man had done no more than pull his hand back. That was enough for two white cops to brutalize him. Then, when he was on the ground being kicked and punched relentlessly, he pleaded with them to stop. They did not until they rendered him unconscious, in what looks exactly like intentional revenge for him not being submissive enough to their authority.
After the beatdown, the cops were out of breath, like athletes who had just run a long distance. They bent down and put their hands on their knees to catch their breath, looking exhilarated.
I watched the video on the YouTube channel of a civil rights lawyer who says this is the most appalling, brutal, sustained beating he has ever personally seen. He posted it to ask his subscribers to please watch and please share with as many people as possible.
He raised the same point than you did: All this man did to rate that brutal beat-down was react in an entirely human way while having black skin.
The two cops involved could have de-escalated at any moment, but they chose not to. They wanted to beat him down. And at the end of the video released to the public, they clearly are very happy they did it.
Here's the version of the video I watched if anyone cares to have a look.
https://youtu.be/WaAVmLSk_8k