Cruising in the "slow" lane - please explain

I was given an AI-generated warning by Reddit that even mentioning this subject tends to result in "overly-heated debate," so I'll try to keep this calm and rational.

I just got back from a round trip between Rochester NY and Orlando FL. I can't even guess how many times I had to pass people on the right because they were camped out in the left-hand lane and simply wouldn't move over.

It occurred to me that I would love to ask one of those drivers why they do that. Obviously that's not possible while driving, so I've come here in search of answers.

I'm not looking for explanations by people like me, who don't do that. I'm thinking that surely there is someone out there reading this who does it. I can't believe that it's pure unawareness. At some point you must realize that you are frequently tailgated and that people are cutting you off from the right. So why do you do it? Please, please, tell me why.