Having police for demographics seems inherently suspicious from a standpoint of liberty as it is either for undue crackdowns or undue lenience separate from official legal status. To give an absurd yet rationally based hypothetical - if it was official that it was in the interest of the state and people for college students to get more lenient drug and alcohol sentences because they want to encourage a limited degree of exploration to better innovation they wouldn't need a seperate police force because it was already codified in law.
This is distinct from when there are actual practical differences for given groups to be policed - a specialized white collar crime police force makes perfect sense as the needs are different. Similarly military police in a provost [https://en.wikipedia.org/wiki/Provost_(military_police)] role are justifiable.
I'm not saying campuses should go unpoliced. I'm saying that the approach is suspect for the situation even if it is just a stupid historical artifact. Keeping an office of a police station on a sufficiently large campus but part of the normal state or city policing is fine - just because they are part of a university doesn't mean they are outside their jurisdiction. Deciding to have a security force that specifically don't have policing powers but enforce rules 'privately' is also fine.