> The way that it appears to be playing out is that parents were repulsed by perverted and strange worldviews being taught to their children on their dime.

This variation of the origin story gets a lot of play. However it doesn't address the outside book-ban groups who provide titles to parents - or who just appear at school board meetings themselves.

    Eleven "super requesters" — those who raised concerns about or challenged
    15 or more titles at a time — accounted for 73% of the targeted books. 
    They often referred to lists of books originating in other districts 
    or from online forums. Some had no children in the district. 
    In nearly 60 cases, the school district didn’t own the book 
    the requester sought to remove.