Witches VS Patriarchy

to be honest, I think we probably share fundamental views on how we see people around us - the difference is in how I relate to and understand my views

You have naturalized sexism, you think because humans are naturally sexual beings that the situation of girls being sexualized is natural too.

I don't disagree that humans are generally sexual creatures (though obviously asexual people exist as well), and I agree also that children have sexualities - but we are talking about why girls have a bunch of extra rules like not being able to wear white shirts, not being able to wear two-piece bathing suits, and requirements of wearing shorts ... this isn't just because humans are naturally sexual, this is because in our society we see boys as wanting sex, and as girls as having the sex that the boys seek.

The rules are seen as protecting the girls from the boys, which positions girls as sexual prey and boys as sexual predators. It views girls as having a virginity that must be protected.

Even within this view, the idea that the solution is to police the girls puts the responsibility on the girls for the boy's perceived predatory behavior.

Why is sexuality "bad behavior"? And if we agree it's bad, why do the rules focus on regulating the girls, why not have rules that regulate the inappropriate behavior of the boys instead?

And of course you're right that the asymmetry of how girls are sexualized and viewed as prey from whom boys "take" sex is a very hard problem to solve, not a problem we will solve individually or in our life times, but big cultural problems have shifted before - we used to not think of women as human at all, Aristotle posited that women were malformed, defective men who were unable to wield their will and require a man as a master to control them for their own good. Hegel opined that women are essentially like plants, whereas men properly belong as animals. Women were excluded as belonging to "humanity" in the ways Enlightenment thinkers articulated it, and were structurally treated as subhuman - unable to vote, own property, etc.

It's only very recently that in the West women were permitted to get an education or have a job, these were huge cultural shifts that occurred due to feminist activism, including violent campaigns of bombings and arsons by suffragettes.

Despite the progress made, there is much more work to do - and the feminist movement is far from reaching the gender egalitarianism it aims for. One of the problems that stand in the way is the continued belief that our socially arbitrary and sexist norms are actually entirely natural (something Aristotle said about his views of women, too - mind you, his views on women were explained through biology, as were the dismissals of women experiencing PTSD from sexual trauma as "hysteria").

If you wanted more to read on this topic, I recommend Julia Serano's Sexed Up for the way it analyzes both the gender binary and the predator / prey mindset.