The post you are responding to is about punishing the victim because teachers are too lazy/cowards to punish the culprits. Cams incentivize them to do the right thing.
Even if the situations are noticed and seen fully, does it cause the schools to not punish the victim? The stories I've heard about zero tolerance policies were that _even when the situation was fully obvious_, victims got punished because they took part in an altercation.
The video evidence is just one piece of the puzzle that is needed to help administrators properly adjudicate conflicts, and to help the public hold the administrators accountable.
If the rot is so deep that even who was right and who was wrong does not matter, then that is a separate issue that members of the public need to sort out with each other.