It is nothing short of a bald-faced lie to suggest that the police were prevented from leaving. The officer who sprays the line of students sitting (unmoving, peaceful) on the ground steps over them first. He could have simply walked away, left them to their own devices, problem (not that I could see an actual problem) solved.
I mean, how long are those kids going to sit there on the path? And in any case, how is it a problem to sit down in protest? Let them sit, let them chant, let them have their say.
They do have a legitimate point to make in any case, the rich *are* too rich. And the poor *are* to poor. However you think that this situation came about, there can be no position taken other than that this disparity represents a huge problem. Pepper spray will not solve it.