As a private institution, Vanderbilt University has every right to curtail certain Constitutional guarantees on its campus. Students, faculty and staff voluntarily join the Vanderbilt community, and therefore they come in eyes open to the fact that the school will limit both their freedom of assembly and freedom to practice their religion without interference.
If people don't want those Bill-of-Rights basics abridged, then they can go to school or work somewhere else, because Vanderbilt does not operate as an extension of a state government, as do public universities. The irony that Vanderbilt essentially uses the guarantee of free assembly as a protection for its policy to take away that same guarantee from its student organizations is lost on university administrators, but then most things usually are.
Does this mean that the Northwestern University Wildcats victory over the Commodores -- achieved by scoring 10 points in less than 40 seconds with under two minutes left in the game -- is actually some sort of divinely-instituted or karmic justice? Well, I'd never say that. But I have the right to.