“Nowadays I doubt this is much of an issue, as it seems that kids get on social media to find roommates and learn about the various dorms.”
At least one pair of working-class girls in the dorms knew they were rooming with each other, so they wouldn’t have reached out to find roommates.
I don’t think it makes you a dummy if you don’t realize that there’s relevant information that the school knows, but doesn’t tell you. It’s reasonable to me that 17-year-olds think a highly detailed freshman housing page with instructions about how to choose your dorm would include all the information you need.