alt Hacker NewsIt's not price fixing. The seller is still completely in control of the price, but they cannot discriminate against Amazon by selling it cheaper elsewhere. Or they can, but then Amazon don't want to do any business with them.
These kind of contracts are standard for all kinds of third party marketplaces. You don't have to sell through them if you don't agree with the contract.
It would be discriminating against Amazon if they sold it somewhere else for less revenue. As in, retail price minus store fees is a lower amount.
When the price advantage is the size of the fee difference or smaller, that's fair and good for competition and I support legal restrictions on contract clauses that want to block it.