If you look at the video, the campus police are surrounded by protesting students. The students were also asked to leave and they refused. They were violating campus policy by setting up the camps, which the head of the campus initially ignored. When the police were told to remove them, the students would not leave. So they got pepper sprayed.
Now comes along this video where one of the protesters basically said they provoked the pepper spray. It was their intended purpose all along.