As a matter of law, schools have the right to demand that off-campus groups not conduct demonstrations ON CAMPUS.
It’s state property, but you can’t camp out on campus, or the governor’s office, just because you want to.
Yes, you have free speech rights, but their are property rights too. You may not like it. It is the law.
If other groups are allowed on to propagandize but Christians aren’t, it’s against the law.