Maybe college is about learning stuff and having a roomie to challenge and help you. I doubt the powers that be are worried about you wanting a long-term relationship.

Remember that people having sex while not married has only been acceptable for perhaps 50 years to society, which post-dates many colelge buildings. There might be lots of people who want to dissuade people from "illicit liasons" by pairing them up in rooms to make things harder ;-)