Questions about odd rules for college student tenants?

[Mark Hu]

I've heard many former students tell me some odd rules in apartments run by universities. One is that student are given individual leases even if they are roommates. Two is that the management can decide to 'remove' a student roommate from a lease for good cause.
In regular rental business I've never heard of having individual leases for a group of roommates sharing an apartment. Also I've always heard a landlord should let roommates sort out their own issues, that it was bad business for a landlord to try to decide which roommate was good and which was bad. So what gives? Are these odd rules true, and if so why do university associated apartments follow these rules?