As the OP said, we have no idea what happened before the beginning of the video. Plenty of folks have led the police on chases, then run into a crowd screaming "police brutality" and "I did nothing!" while the police cuff them. All the crowd sees is what's in front of them, which is a "victim" being "abused" by the police.
The same goes here. Let's refrain from general commentary on the situation until we have more information.
Sometimes it’s nice not to destroy the world for a change.