>Why is Bonnie so sexual?

She isn't. You are projecting your own lust onto her.

IRL something like >>26887155 would all but destroy Bonnie's heart and soul. Girls AND boys who are exploited by their relatives have a heavy baggage that they can never cast off by themselves. Drug use, addictions, dysfunction, mental illness... all commonplace in adults who were molested or raped by older siblings, uncles, parents, etc.

It takes years of therapy in order for these people to have any kind of a normal relationship ever again... if ever. Some never make it.