That would depend on what statute the protesters were arrested under and if would have applied to protesters of another ilk. If they were arrested under trespassing statutes, then it’s safe to say that it was not illegal. I can protest you if I want to, but you’re under no obligation to allow me access to your property to do so.
So you’re saying that Liberty University IS required to allow people with opposing viewpoints on to their PRIVATE property to practice beliefs contrary to their mortal foundations? As a private institution, Liberty is legally allowed to determine what groups can assemble on their campus. And what groups can use their name for activities.