That’s one thing lay people don’t seem to grip. Cops live or due by their departments SOP. An officer can do everything legal but if something he/she did violated department policy they can be fired.
I believe that when he resisted and got back into the car had they let him go with a “we’ll get him next time” mentality and he mowed down a bunch of old ladies or kids, there most certainly would have been a massive outcry. Especially if video of the officers letting him go surfaced.
The public wants it’s cake and eat it too. They want to be safe from criminals but then question the manner in which that safety is provided. They don’t like the answer “it was time to not be nice.”