Two words: public schools.
Your grandson is proof positive that the leftist indoctrination forced upon school children is effective enough to undo all of the careful home education and moral teaching of parents, grandparents, and pastors.
There are other contributing forces, but those in the public schools are by far, the most powerful, and should be avoided by decent patriots at all costs.
Sending your kids to leftist indoctrination camps run by perverted communist scumbags (public skools) is a form of child abuse.
If you can swing the cost, send them to Judeo Christian run schools or if not home school them.
Its way past time for the right to declare war on public schools