I wonder why the students, or the parents or guardians, can't file a sexual harassment suit, or at least say they find the displays "offensive," and demand that they be removed from the classrooms. Hell, that's all the leftists need to refer a conservative to "sensitivity training." Just say you're "offended."
They'd probably be better off with this one:
US Constitution Article I, Section 10 -
No state shall enter into any treaty, alliance, or confederation; grant letters of marque and reprisal; coin money; emit bills of credit; make anything but gold and silver coin a tender in payment of debts; pass any bill of attainder, ex post facto law, or law impairing the obligation of contracts, or grant any title of nobility.
(If you think caring for & raising your children isn't a legal contract, try NOT taking care of them!)