I did not see anything on that video that suggested that he needed to have a knee on his neck for any extended period.
It will be entertaining to watch the folks on FR come out and defend killing a guy in handcuffs.
He might have committed forgery! I wonder what the good ol’ freepers would say if a cop treated a mask protester that way - crushed his windpipe while handcuffed in front of a crowd. Would the deceased be the ‘perp’? Would it be resisting arrest or resisting tyranny?