Holly is not a virgin to sex, just very inexperienced, and I will grant you that she becomes more confident faster because of sex adventures.Isn't that wanting to eat your cake and keep it, too? Holly gets confident because of successful interactions with people. It makes little sense to want her to be confident and yet stay a virgin who never sucked a cock in her life.
Holly isn't "ran through 3 guys". She fucks. Like pretty much everyone else in the cast, so not sure why it's suddenly a problem when it's her.
With Holly it is not about just sex, she lacks confidence period.
As for why I care... unless you want an open swinger relationship ingame (I don't), I tend to think that if a person is used to having multiple sexual partners, they are less likely to be faithful in a monogamous relationship where her significant other expects her to be so as they also intend to
Sex becomes more of a commodity or turns people into literal sex toys and nothing more.