Why it would be a threat? Unless Amazon is manipulating the marketplace for the customer to buy a product different from what they want. In that case such practice surely should attract a look from regulators?
If you insulate humans from the manipulative dark patterns (though agent intermediaries), it's possible for them to spend less, spend more efficiently, optimize out information-asymmetries that are profit centers for entities like Amazon. Of course Amazon will fight this.
There is no expectation or regulation that a store is supposed to only show customers what they want. A retailer is going to sell you the items you're willing to buy based on what they think will help them drive the most profits.
Imagine for a moment you're a store that sells millions of different products. Now, imagine a customer walks into your store, and as per some government regulation "you're expected only to show the customers who walk into your store products that they want". It's a fairly ridiculous expectation.