It doesn't. Pointing out the contradictions in fascism doesn't stop fascism because they don't care about contradictionss. They care about enforcing an authoritarian ideology on everyone, and to that end everything is permissable. As long as they're still intent on securing power, their followers don't care. It's not about being right or making sense. It's about seizing power by any means. In a democracy, that means saying whatever bullshit you have to to keep your followers engaged.
Making fun of them for their contradictions does nothing to stop them. Not taking fascist movements seriously and expecting them to go away because their beliefs are silly is what Germany did when Hitler was rising to power. It's not a good strategy.
I wonder if many/most of these will get vandalized, or if public school kids are so checked out and apathetic they'll simply be ignored like they ignore the teacher, the textbooks, and pretty much everything but their phones.
Whatever happens, I don't think it's going to put the ass-kissing "fear of god" into any of them. Waste of tax dollars.
Of course the real point is to "own the libs" and anger atheists. Because Republicans don't really accomplish anything else.