Sexualizing children is the problem. Good grief.
I don't see any sexualizing kids but a lot of denial we are sexual beings and kids as well have curiosities and questions. And somewhere this absurd idea that elementary school students are innocent. Of course there are age appropriate things, and it's unusual for very young children to know more than just the iew, icky, gross, boys and girls ugh type stuff, but they are still curious about some things and it's ok, and even good for them, to know that it's normal and natural for people to start developing certain feelings and attractions towards others when they grow and get older. Concepts of romance and marriage are also good to know. They'll iew and yuck, but it's important they receive messages and reinforcements these things are normal, natural, amd will come later on.
Fifth grade, the entire male student body in my classroom got a lecture about inappropriate sexual behaviors when they did harass the girls of the class.
So, yeah, even young it is appropriate for non-explicit material that prepares students with knowledge and resources against predators, and the differences between wanted and consensual things and unwanted, non-consensual things.