The bill contains a large number of things within it.

After third grade, there is some expectation of health-class discussions, so no outright banning of content. Instead, they must disclose the curriculum to the parents of all the children and have it approved. In addition to this, for all grades, it bans the discouraging or forbidding of children/students from talking to their parents about things discussed in school (the fact this is even necessary is obscene).

The K-3 restriction is just one element, a blanket restriction on all sex content. No teaching little timmy how to take it up the ass, and no teaching little sally how to take it up the vaj either. Just a blanket restriction on sexual predation regardless of the pred's predilections. But middle school may require some topics of such to be breached in health education, so that blanket ban wouldn't work there.