> I don't agree any of those things should be taught in 3rd-5th grade because I think it is much more important to exercise the fundamentals of critical and creative thinking, logic, imagination, etc. at those ages.

That's exactly how you develop it. You teach complex concepts which require kids to sort truth from fiction. You don't teach one. You teach many.

> I also have a big problem at any level of schooling with these unscientific and unproven "theories" (if you can even call them that) being taught by people who have entirely bought into the cult thinking and have no ability to critically reason about them let alone the desire to.

I agree.

> Would lessons about socialism and collectivism teach why the system can generally only sustain itself at a state level by devolving into a single party police state dictatorship in which the people most certainly do not own the means of production? Doubtful.

You're generalizing an awful lot from n=1. We had the Soviet Block. That's the only time it's been tried. It'd be like evaluating liberal democracy from the French Revolution or the current collapsing Afghani government.

> It's like inviting a white supremacist to teach children lessons about nazism. Or a creationist to teach biology. Or a flat earther to each geology. Not a helpful lens at all.

I teach my kid those alternative theories too. I do a sincere job of it too. He doesn't believe me, in part due to other adults in his life.