Folks, you DO know there are some states where "creationism" is taught in schools, right? Even when I was in high school in a relatively "liberal" (in the American sense) window of the late 70's very early 80's, history, social studies, government, all those classes has a fairly jingoistic undercurrent. I know quite a few folks who are or were teachers in the US, and what is and isn't included in the curriculum, and the constraints placed on individual teachers to keep them "on message" must have a big impact on what people absorb.
And then there's the rise in "home schooling" and increased popularity of fundamentalist Christian "community" schools and bigger academies, that aren't subject to the same regulations as state schools. Seriously, there's been a couple decades now where fundy parents are pulling their kids from state schools to shield their precious children from Godless "liberal" teaching on stuff like science, sex and relationships, social studies, etc.
I'd say what is and isn't in the curriculum IS pretty important.