transphobia, lies to children
Y'know, the more I look at conservatives' constant railing against "political correctness", the more I feel "there are only two genders" is basically the adult version of "Santa is REAL, damnit!".
It's like a shit sandwich of bigotry meeting with a complete unwillingness to realize that one's previous conception of the world was wrong; rather than just throwing an ineffectual tantrum however, instead they try to change the world itself to conform to their own views.
transphobia, lies to children
Of course, education alone isn't the only way out of this; there's still centuries worth of tropes to reinforce that shitty mindset. But just as much as with any other kind of bigotry, it would at the very least help those people who genuinely don't know any better.