If anything the campus groups are risking slander and defamation lawsuits

Not even close. This is a for-profit business, and if students don't feel safe, they have a right to voice that opinion and provide that feedback. If the college stands to lose enough business over this, they can absolutely refund his tuition and cut him loose within the terms of service described when he signed up for classes.

Slander and defamation suits are very hard to bring against individuals expressing their subjective opinions. Me stating I think Rittenhouse is dangerous is not slander, and to suggest otherwise is ridiculous. I think the disinformation you are pushing is dangerous as well, suppressing free speech and the ability for people to express subjective opinions.

If they came out can called him a murderer over and over, and published it extensively in a bad faith effort to defame him, well that's another story.

This petition says nothing of the sort, it expresses the opinion of classmates that they do not feel safe, and they have every right to express that opinion no matter how invalid you think it might be.