...and what on earth do these "parents" think schools are teaching kids?
"Now, little Timmy, since this chapter concerns women's fight for equality, you must be a princess for a day." No, that's not what's happening. Teaching about fairness, love, acceptance, and equality is not equivalent to "grooming."
"Keep the kids out of it!"
Out of what? Following the Golden Rule, regardless of a person's age, sex, race, gender, creed, or orientation? Be nice to people. Oh, the horror!