Yeah and I think it is clear which point deserves more emphasis: Point A is that the student was acting like a bitchy teenager and her actions initiated the police officer's involvement. Point B is that the police officer went nuclear with a bitchy teenager being a bitchy teenager and used an entirely disproportionate amount of force. Any disagreement with the statement of Point A or Point B? No? Good.
Here's why Point A basically deserves the emphasis of "So What?": there have always and will always be lots of people who for selfishness, assholishness, general stupidity, or whatever reason do not comply with societal rules. This is not groundbreaking. You know how I know that? Because there have been literally millions of men and women employed in law enforcement over time to respond to these people.
Here's why Point B deserves emphasis: This guy is employed, meaning specifically plucked out of the milieu of dude's just existing, scratching their asses and doing power cleans to kill time, given a paycheck and a pension, given a gun, and given special authority to detain people and use force against them. And he just showed why that was a really bad idea to employ him at a position that provides so much public authority and trust.
THAT'S the point of why this should be somewhat alarming. Maybe not this one dipshit as a single example, but as part of a systemic issue that we now see more because everyone has a video camera on them at all time.