I'm confused as to how eBay banning the listing of these books materially impacts people from getting them.
This is the "just make your own ${thing}" repeated in the past where ${thing} has progressively moved from: forum, messaging system, website, cloud service, internet platform, ISP provider, ICANN membership etc.
Because it's okay, approved and society thinks its good for one store to stop doing it means that it's okay for other stores, services, provider etc to also do it. It will and does happen as we have seen on Hacker News every week.
It's the same reason we get angry at people for saying racist crap even though we believe in freedom of speech.
People are free to be mad at eBay for removing the books from their platform and eBay will take some hit for it. I suspect that they think the pros outweigh the cons with this decision, however it was calculated. This is just business as usual.
I wish more folks understood it's the companies themselves who are overreacting. Trying to fix people on the Internet is an unsolvable problem. Demonstrating to companies that outrage is almost always temporary and not business-impacting seems achievable.
The line is still where it was the entire time: private individuals and entities are allowed to decide for themselves with whom they want to associate. You seem to have made a huge leap from "eBay decides to stop selling a book on their platform" to "Big Tech is deciding which books we're allowed to read to our children". That simply isn't what is happening here. As always you are free to read whatever you want to your children, and you're free to listen to Alex Jones all day every day. eBay is free to decide what they want to host on their platform. Everyone is free to exercise their own individual freedoms.
This is the marketplace of ideas at work. In the marketplace of ideas, some ideas float to the top, others sink to the bottom. The sinkers and swimmers change over time as the buyers and sellers in the marketplace change. These books had their time, now they are sinking. The same goes for Alex Jones. He got his shot in the marketplace, and his ideas found a home, but they aren't for everyone and that's the choice of individuals in the marketplace.
Don't you think that the owners of websites should have the right to control what content is on the website?