Anyone remember this, back in 2011?
https://yro.slashdot.org/story...
They decided to stop selling Yaoi manga. For anyone not aware of the term, it's male homo-erotic manga. However, they didn't stop selling Yuri - the female equivalent with homosexual relationships between women instead of men.
It struck me at the time as blatant homophobia on the part of Amazon, I never bought any yaoi or yuri from them in the first place, but after that (and various other shady practices, like their remote deletion of copies of 1984 that people had bought on Kindle) I stopped using Amazon at all.
Now you can of course argue that it's their business, and they are free to sell or not sell whatever they choose - and that's absolutely fine by me, in fact I'd disagree if you tried to force their hand in terms of what they can sell or not. By the same token though, I'm free to buy from them, or not. I don't.