Hef targeted young women who he could easily control with money and fame. I think to some extent some of the girlfriends were caught up in a lifestyle that seemed unlikely for them ot have without him.
The majority of them also came from some sort of broken home with childhood trauma. It makes for a lot of risky behavior and people who can be easily manipulated.Survivors? They were thrilled until the fame ran out.
I agree, not everyone can be strong and feisty out of the womb, yet most would not whore themselves out to a man 60 years older who was a drug addict, controlled their lives, bad at sex and lived in squalor and disease. All to be on a TV show.