Publicly traded companies are private property held by members of the public who are private citizens, so even if they are a monopoly it doesn't really matter, because then they should be broken up, and they will still have the agency to choose which books to sell.
But there is a difference between starting a book store that delivers any book you want and forcing every private bookstore to sell all books.
They key is you want to supply every book I dont imagine a evangelist bookshop would like having to sell "How to raise a child as a Homosexual couple"
Publicly traded companies are not private businesses. Especially when they hold monopoly power.
Publicly traded companies are private property held by members of the public who are private citizens, so even if they are a monopoly it doesn't really matter, because then they should be broken up, and they will still have the agency to choose which books to sell.
And the agency to decide who should be punished for reading books they choose not to sell, right Mr. Slippery Slope?
How would Amazon legally punish a private citizen for reading a book that Amazon has decided not to sell?