Grades 4 thru 6 are considered a prime educative sweet spot. Up until grade 3 kids are learning how to read and write. At grade 7 the hormones begin to kick in. So, grades 4-6 is the best time to teach the most important lessons.
The mis-educators know this and work pretty hard to implement the stuff they really want the kids retain for life.
Like anal sex.
Think of the kookiest, weirdest sexual practices out there.
Now, why would you "teach" CHILDREN about them?
Fine if they were adults, discovering the "joys" of coprophagia or golden showers. Let them purchase whatever weirdo magazine or visit whatever kinky website they want.
But leave the kids ALONE.
Darn, I missed out on so much. Didn't so much as kiss until high school. And never did any anal sex. It's a wonder I got through life. (Now I have to worry about my grandkids and what they will be taught.)