Long a rather quiet affair, over the last few years "banning" has become a major issue, with one group often portrayed as the culprit: conservatives.

But it is not conservatives, or "banners" of any political stripe, that are the problem. It is public schooling itself.

You are probably familiar with the typical battle: parents at school board meetings calling for the removal of books from libraries, recommended reading lists, or class assignments. Members of Moms for Liberty, founded by three mothers and former school board members, might be the best known activists fighting to restrict books such as Gender Queer: A Memoir, about author Maia Kobabe's journey of sexual discovery.

The many battles that have been fought over Gender Queer, which free expression watchdog PEN America reports was the fifth most challenged book in the last school year, are classic culture war: a clash of irreconcilable values.