I am grouping together "everything that goes into your brain," which includes lots and lots of stuff, most of it unconscious. See research on priming, for example.

This argument is explicitly about encouraging people to justify ignoring relevant data about reality. It is, I recognize, an extremely dangerous proposition, of exactly the sort I am warning against!

At risk of making a fully general counterargument, I think it's telling that a number of commenters, yourself included, have all but said that this post is too dangerous.

• You called it "deeply worrisome."
• RichardKennaway called it "defeatist scaremongering."
• Emile thinks it's Dark Side Epistemology. (And see my response.)

These are not just people dismissing this as a bad idea (which would have encouraged me to do the same), these are people are worrying about a dangerous idea. I'm more convinced I'm right than I was when I wrote the post.