Besides "dedication to a cause," there are other reasons why students join protests and demonstrate. Here are a few:
1--Most student uprisings come in the spring semester. For many a student they present a heaven-sent opportunity to get out from under pressures in tests, term papers, lab reports and lecture notes that have been accumulating since the opening of school in the fall. In May and June the moment of truth is fast approaching--final exams and critical deadlines.
2--Love of excitement, escape from boredom. There is a lot of boredom in schools.
3--Temporary switch in campus roles. "Mice become as lions, lions become as mice." Some students become instant authority figures ("big man/big woman on campus") in place of chancellors, presidents, deans and professors. Many students find this a thoroughly satisfactory state of affairs, even though temporary.