From what i understand the vast, overwhelming majority of students were protesting against the Dengist reforms.

About 300 people died, including PLA soldiers, in street fighting blocks away from the square, which started when unarmed pla soldiers were attacked with firebombs in their trucks and apcs and burned alive.

The students in the square left when ordered with little if any violence. The whole narrative around the June 4th incident is unalloyed propaganda and revisionist history.