Well, when parents find out books like
this are in schools, the schools blow the trust. And the reaction from teachers and schools when parents ask just WTF is going on here has been, "none of your business, I am the teacher and I know what is best for your child...." then parents are going to clamp down on the schools.
As to government involvement, public schools are literally run by the government. There is no other way to address what happens within them other than involvement from the government.