Most Americans can't fuckin read.

If fucking only. ForwardsFromGrandma would be far less pernicious if they couldn't.

Half the country can't read above a 6th grade level

The content 6th graders are expected to read has escalated dramatically from decade to decade. Americans have no problem ingesting large, often sophisticated, written narratives. Reading comprehension isn't the problem.

The problem is that much of what we're presented with is bullshit. Garbage in, garbage out.

Getting through the Bible cover-to-cover is hard work. Grasping the various mysteries and allegories and heavily dated metaphors is harder still. You can have a masterful understanding of Biblical literature, of history and interpretation and theological significance. So fucking what? You're still using a fairy tale as a first principle. A doctoral thesis in Angelology might involve ten thousand hours of research in a dozen dead languages. Who cares, when the subject matter is pure myth? What does it matter that I can finally convincingly answer the question "How many angels can dance in the head of a pin?"

Also, dunning kruger effect is part of it.

Its the blind leading the blind. I read a textbook by Larry Summers while earning my masters at the University of Chicago. I can talk circles around your lay Marxist. I can Do The Math that makes neoliberal theory plausible. I get a job teaching this theory to my students, in between speaking gigs at business events and interviews on talk shows. Everyone gets to receive my erudite understanding. No one can question my genius.

But when the foundation is made of turds, so what? What does reading comprehension help you with?