As a sheer tactical matter, mass arrests of the protesters seems to be having the opposite of its intended effect.
That’s because they’re released with a small fine, if anything, and a warning not to go back. There’s no actual consequence other than the mild inconvenience the booking process and night in jail, which is what they want to experience anyway so they can feel like persecuted revolutionaries. If they violate the trespass and return it should theoretically be a more seriouss offense but with “bail reform” they’ll just be released with a notice to appear (if the DA even prosecutes). If there is no punishment, they’ll just keep going back. You’re right that the current method of arrest is ineffective, they need to make the arrest process mildly uncomfortable, Water hose / tear gas for anyone refusing to disperse, pepper spray for anyone continuing to resist arrest. Of course that brings up liability issues. Columbia just needs to expel them and turn on the sprinklers to water their grass.