A few questions and some observations.
Of course, the obvious, why was a child at a protest to begin with?
How much was the increase in the fees? (Knowing DUmmies, probably $5.)
How old was this Santa Monica "student" to have a 6-8 year old child?
The cop appeared to be holding his ground guarding a door, in an entirely DEFENSIVE position. IOW, HE was attacked first. Action=reaction, baby! Read Newton's Law.
The protesters look to be ANYTHING BUT peaceful! Most appeared to be 20ish and up. The guy under the firehose at least 30+.
Protests are held OUTDOORS, not in the lobby of an administration building.

In short, the parent didn't bring the child to a "protest". This wasn't a "protest", it was a mini-riot.
http://electstevedawes.com