I completely agree. Its deeply entrenched patriarchal feelings about girls sexuality that even most progressive parents still hold. The author of the books admitted that she felt impulses like that with her own daughters, but really pushed herself out of her comfort zone because the evidence is so overwhelming that this is harmful to girls, not just in not really have much sexual pleasure, but in having uneven power dynamics in relationships, in being more susceptible to rape culture, etc. It's overwhelmingly clear that the more information both boys and girls have, the more responsibly they behave around sexuality, but for some reason here in the US, we really don't want to acknowledge that.