I think it's more than that.
One of the best documentaries on any subject I've ever watched is Heart of the Game (2005). It follows the single season of an elite high school girls basketball program and all their highs and lows. I can't recommend it enough, regardless of your interest in women's basketball. It's just great storytelling.
In there, the head coach talks about how women are naturally averse to physical contact. Boys grow up naturally roughhousing. They thrive on physical contact for the most part. But for girls it's not generally in their nature. So the first practices he literally just has them back to back, physically contacting each other to get more accustomed to it.
I think that's part of the huge draw for volleyball over other team sports for women. It still demands a high degree of physicality. The same aspects that are demanded of an elite basketball player are demanded in volleyball. Height. Ability to jump. Twitchiness. The ability to move quickly across the floor. There's plenty of competitiveness. But there's not the constant need for physical contact that basketball demands. No one says this, but when these young girls play both sports and so often naturally gravitate towards volleyball as the sport they prefer, it's my opinion this is a lot of what's going on.
I also feel like indoor volleyball tends to attract a higher percentage of girls more in touch with their femininity, whereas sports like basketball and softball (especially mashers) seem to attract more women who are comfortable with more masculine traits. But that's only an opinion. It also wouldn't be clear how much of that is wiring, and how much is socialization, just like all human traits.
The other astounding thing to me is how strong the gay community is in volleyball. I never would have even thought about it except for my interactions on volleytalk. I don't know this for a fact, but it seems obvious to me men's volleyball is more open to the community than say, football or basketball are.
All of this can get kind of touchy in ways I don't intend for it to. They're just my observations. Doesn't mean they're correct.