Now that I've read the raws again the pages where Ryou is explaining things is kind of a mess
http://dynasty-scans.com/chapters/opapagoto_ch02#39
Being locked in.. -> In a closed environment like this there is obviously going to be those who become frustrated
and they get pregnant -> Nobody wants to get pregnant and get expelled and even more,
So, girls hitting on other girls -> there are plenty of girls who fall in love with other girls too
Next page:
getting popular -> When you go to school this monday you're going to face a little popularity yourself
Basically, while the family system might be fake the romance can be very much real