@Aleph Not gonna go step by step but oh well: Religion is a disease from a consequentialist perspective in the present day. Its primary function in the modern world is to enable myriad, nay, INFINITE varieties of abuse and coercion (physical AND metaphysical)
Sexual education is not anti-religious but it clashes with religion in making people less susceptible to coercion, and less likely to tolerate or make excuses for abuse and be more empathetic to victims. This results in fewer victims continuing to be religious, and fewer witnesses of abuse continuing to be religious. (this effect happens where it is most valuable; at the intersection of religion and fascism, because like I said, the point is to fight authoritarians, not to fight religion)
I'm not here to police vices I'm here to mitigate harm, and harm doesn't need to be reduced to 0 to prevent the future you're worried about in the OP.
Irrellevant quip: Religions are a monolith in the way that matters; they are monolithically factually wrong.