This is partially on the author, and I say this as somebody how writes as a hobby. It's not too difficult to publish on the Kobo store, and there are other stores out there. Of course, it's difficult to compete with Amazon when it comes to reach and to some small features, but they are no panacea either. For example, they don't support epub 3 with aural synchronized media, and they do something terrible to images embedded into ebooks that make them frankly useless. And they charge authors an outrageous amount for kilobyte of ebook content.
I believe Amazon impose a whole bunch of conditions on people publishing on their platform. Along the lines of exclusivity and controlling where else if at all you can sell it. I'm pretty sure Corey Doctorow extensively covered this.
Yes they do. One particularly annoying one is about pricing: price can't be zero. If you write as a hobby and don't care about making a dollar, then Amazon gets in the way. Sure, you can publish in Amazon and charge 1 USD, but then you can't publish your book on your own website for free because it goes against Amazon's TOS.
There are other peeves. Covers for example: it's against the TOS to have a cover that shows female nipples, but it's okay to show male nipples. Beyond the sexism of the rule, I'm worried that the way to enforce this is to have some ML system checking all the covers and making judgements about nipples. Which means you have to ask your cover artist to not draw anything that may accidentally look like the wrong kind of nipple \o/ .
