It is the pinnacle of the zionist-influenced "college experience". These females, who you call "hot", are naturally very in touch with culture and wish to never stray from the cultural norm. They're finally away from their fathers and mothers, and are free to do as they've been programmed. Sororities give these women free and guiltless access to indecent behavior, alcoholism, indiscriminate sex, drugs, and other general degeneracy that ruins females to the core. In high school, the "elites" were pretty cut and dry, but in college, there's a whole legalistic system for the elites, and that is frats/sororities.
Anyways, you should re-evaluate who is "hot" in your eyes. I personally find females who partake in that life disgusting whores. I described above at what these women end up doing... is that really so "hot"? I don't think so. When I was in college, the most attractive females I knew were in my bible study group. They were feminine, thin, and at least feigned chastity (blessed are the men who get these women!). In my experience, sororities has just as many fat entitled bimbos as "hot" girls, who were only hot for their slim bodies.
Lastly, it supposedly offers networking opportunities which I am unsure if true. I can definitely verify that networking gets you ahead in life (I'm one of the two full time engineers in my whole office who was NOT hired due to nepotism/connections), not skill, so the allure of networking draws people in.
I should end by saying I went to a medium sized state school in Ohio (not Ohio State) and your experiences may be different if you go to a large school or maybe a private school. My university was rather "good" for a university, though that's not saying much.
Not sure what class has to do with it. Frats at my college had poor blacks from the hood, ugly soyboys, and poor foreigners. Some of the dudes I'd see at football games with frat flags and shit straight up belong here. I knew a guy who was in a frat that had LoL LAN parties. Very truecel shit brother.