Yes! We have this standard. It's called "laws". We elect these people called "representatives" and if we want people to not be able to buy or sell certain things like a kilo of heroin or a machine gun, we have them make a law that prohibits it. This way the public has input on the process and it is not left up to the arbitrary prejudices of any particular corporate drone.

eBay is not selling anything. The users on eBay are selling things and they can choose what to sell or not sell. If Wal-Mart wants to decide not to sell the book, fine. If you purport to offer a marketplace where other people can sell and buy things, you should not be involving yourself in the customers' transactions unless they are illegal.

Ok how about this, should my local farmers market be forced to allow me to set a pornography stand?

What horrendous, world-ending catastrophe do you think would occur if someone sold pornography at the farmers market?

If the public doesn’t want to buy porn there, they won’t and the stand will go out of business.

If they do want to buy porn there, why do you think the farmers market owners should be allowed to dictate what adults are and are not allowed to buy?

What if you wanted to set up a stand that sold books exclusively by African-American authors and they told you you weren’t allowed to do that. Is that ok?

There'd probably be a lot less people at the farmers market next week

Its obviously not ok, but its not ok because its racist

Ok, so “racially insensitive” material and explicit pornography are both legal currently. Are you saying that eBay should be forced to allow their users to sell both, or are you saying that we enact a new law that says that eBay should be forced to allow their users to sell “racially insensitive” material, but not explicit pornography?

I'm saying that if you position your business as a platform or conduit through which people exchange things, whether those are physical goods, IP packets, fragments of text and images, whatever, you should be a "dumb pipe". Such businesses should not be permitted to abuse their privileged position to impose their own will on the general public. Remember Net Neutrality? Same thing. If you want to sell a stack of old Hustlers or a copy of Song of the South it should not be eBay's place to tell you that you can't.

eBay is not the government. They are not arbiters of what we are and are not allowed to do. Many people have sacrificed their lives to ensure that we are not governed by arbitrary tyrants that we have no say in, and it's frankly shocking that people are now like "Well, they paid a lawyer to set up a C-Corp in Delaware so I guess it's fine that they decide what we're allowed to read now".

It’s not just old Huslters. If eBay were not allowed to prevent explicit pornography from being sold on its website, it would have a much less valuable business, and fewer people would get value from it. Just as an example, it would end up being blocked by “family friendly” web filters that are popular with businesses, schools, and families.

Unless you think that businesses, schools, and families should also be prohibited from blocking pornography, or should otherwise be forced to facilitate access to eBay, your suggestion is untenable from a business perspective.

eBay is undoubtedly blocked by numerous work filters because it is not really relevant for doing most jobs. They manage just fine.

Besides this is a ridiculous strawman. "If you allow people to sell Dr. Suess books, you must therefore also plaster the front page in explicit pornography." Obviously not.

The Internet is increasingly winner-take-all and is controlled by fewer and fewer larger and larger companies. Allowing a handful of corporations unrestricted reign to dictate what we are allowed to say to each other is antithetical to a free society. Reductio ad absurdum arguments are not going to help you when cabal of corporate censors with no accountability decide to eject you from society for daring to question the intellectual fashion of the moment.

I have not made a straw-man argument. Laws must be written precisely, and it’s entirely appropriate to test proposed changes to law by applying them to specific cases of fact.

You may have identified a real problem in society, but you have not proposed a viable solution.

I would just like to point out this terminology used:

"forced to allow"

vs.

"prevented from denying"

Think about that difference.