The last barnes and noble I went to had a liberal shelf and a conservative shelf (not labeled as such, but clearly separated). I live in a county that biden won by <1%. It's clearly a data-driven decision and both sides of the aisle love buying books from their tribe.

But who are those books for? I don’t buy books about politicians I don’t like.

A non-trivial number of people do across the political spectrum. Political memoirs for instance are usually ghostwritten (outside of the first Obama book and maybe the Pete book given he was a nobody) and are only purchased in order to show support for the candidate. It's a team spirit thing.

Plus, I'm sure some have their own niches (satire, exposés like "Frankly we won this election" that have new reporting, etc) and many have their own historical value. I saw an ant-Tom DeLay book in the wild a few years ago well after his fall from grace and considered buying it just as a keepsake of the era.

No, not books meant to paint politicians in a good light. I’m talking about these “orange man bad” books. Why would I want to spend hours of my life reading more details about a man I don’t want occupying my mind?

I do. "Don't like" is not the same as "not interesting".

I read a couple months ago that publishers were being pressured not to publish books by Trump insiders.

Yeah, and that probably didn't stem much of the flow because the rest were published by journalists. If anything some of the insiders' accounts were just as scathing as the explicitly anti-Trump books, which is saying something.