If a school is informed of a student who may be a hazard in the future, the standard of "reasonable doubt" does not apply. Whether they expel him to protect other students from harm, or to protect their financial interests, doesn't really matter. If they allow a known hazard to continue, they are now complicit and will have to shoulder the blame for whatever happens.
Yeah, but so what?
This amounts to accusation = punishment. You find that acceptable?
Yeah, so what? Every job comes with a set of expectations and obligations. A school Admin is expected and obligated to keep the campus safe and ensure the financial survival of the school.
A few years back, Hoverboards were the must have Christmas present. There was no ruled concerning Hoverboards or any other similar devices. When LSU started the spring semester there were two dorm fires caused by Hoverboards being charged. The immediate reaction was to ban Hoverboards on campus. That's an easy call, without regard to anyone's personal right to legally possess a Hoverboard, or the protest, "I don't leave my Hoverboard unattended on a charger." The Amin can't leave a known hazard in place, no matter how unlikely it is to reoccur.
Life is full of judgment calls and you can't please everybody. If nothing else, expelling one student because of a plausible accusation of sexual assault will likely reduce the incidence of such things.
It's been a long time since I've spent a lot of time on a college campus, but I know one thing for certain. In those days, sexual assault, date rape, PYL, etc, was very common. Any time I heard about it, I never doubted the accusation. The standard response to the woman, if she bothered to report it was, "You'll know better next time." Expelling the man involved is basically applying the same remedy to him.