I've not read it, but Google is my friend...
"Cultural Literacy" represents the tradition of pluralism in the United States of America. Hirsch also suggests that critical-thinking skills should always be predicated on relevant knowledge: one cannot think critically unless one has a lot of relevant knowledge about the issue at hand.
Not too long ago in a bunch of now deleted posts, we touched on a topic that is understandably very close to your heart, I have no desire to revisit it, I really mean that.
However, in the course of the "debate" you accused me of lying regarding my association with a particular group, implying that my motives were not grounded in "relevant knowledge about the issue at hand" but motivated instead, to put it mildly, by prejudice.
You are, of course, at liberty to express that opinion, but what it did expose is that progressives view pluralism entirely on their own terms. All the panoply of wonderful, warm and empathetic things they believe and vigorously promote is what pluralism is really all about. All those who oppose these wonderful enlightened things are, at best, ill informed and stupid and therefore incapable of "critical thinking about the issue at hand", they're reactionary, at worst bigots, liars and fascists.
Right now social media is infested with progressives ranting about the terrible state of things and when they're not ranting or engaging in purity inquisitions, they're thrusting microphones at Trump supporters ridiculing how stupid and wrong they are and conversely how enlightened and right on progressives are. While this is all very comforting because it reinforces a simple stereotype, one you alluded to in the quoted post, that the likes of Dax777 don't get it because they're too stupid and should educate themselves by reading "Cultural Literacy" or any book without pictures in it. Have you ever considered that Dax777, and others like him, don't get it not because they're incapable, but because you can't sell it, and that you can't sell it because what you're selling doesn't stand up?