well this is where the parents comes in. and asks the kids below age 10 "what have you learned today?" I do remember getting some forms from teachers saying "i'm going to be teaching them xyz do you want them to be dismissed for that time until i am done with the curriculum" etc etc.

For me this is a 2 way street. Parenting and being responsible to know what exactly your child is learning in school. I doubt this is going to cause any harm, but make kids more aware of progressive thinking. Whether that's dangerous or not who knows. I heard her mention military and the first thing i said was "hoooahhh" so who knows what a kid wants to latch onto.