I think at least some of the girls ended up in the party dorm when their applications to other dorms were not accepted, or there was not enough room in the other dorms. (Feeling lazy - maybe I should take another look at the book.)
Guaranteed honors housing, or other types of special interest housing, is an important perk for many students considering state schools with party tracks. I think that in the past couple of decades, state schools have discovered that themed housing of any sort can be a draw for students. This probably has an unintended consequence of intensifying the atmosphere of party dorms as other students are siphoned off.
I would not underestimate the effect of poor living situations on academic performance and mental health, whether as a result of living in a party dorm, or elsewhere, even though some students are able to overcome the worst effects with support.