We don’t “let them do” anything. They do what they want.
Everyone says that this is like “browser wars.” Yes and no. It’s “browser wars” with a twist — monetized content is at stake more in ebooks than it was on the wide open web.
Activism and public shaming never had any effect on Amazon. Truly. They do not share much in the way of details with big publishers. They’ve always been cloak and dagger about what’s up their sleeve. I don’t see this changing. Especially now that content is a commodity that anyone can produce for Amazon’s ecosystem with Amazon’s tools and Amazon’s KDP support.
We don’t have to like it. Attempting to fight it is likely not the best use of one’s time as a developer. There are other things that we can do with our time that are more useful to the non-Amazon world.
I’m very happy to not have to deal directly with Amazon content these days. I have no problem filling my work week with plenty of things to do without Amazon directly in the mix.