It’s the same with theft, normal assault, fraud, normal criminal behaviour, etc.
Universities often want to keep it “in house” and deal with it through internal disciplinary actions - as opposed to bringing in the law enforcement and public scrutiny.
This exists outside the US too - and doesn’t require a campus police force.
In the university a friend went to, such matters (theft from accommodations, etc) were dealt with through the deans office, and calling the cops was heavily discouraged by the university.
This system has pros and cons, but when it’s to do with more serious matters (actual assault, sexual assault, etc) the real authorities should be brought in instead of some bizarre victim silencing and due process lacking internal system.