> This is true everywhere, like at a grocery store - it would be a silly article if it complained about more expensive or store-brand products being placed at eye-level when a "better deal" might be 3 shelves down

Ok, let's look at this example to refocus. I agree with you that OP is mistaken in their analysis - that you can't jump from the most popular item to knowing that item is best for everyone. But I think we have switched onto talking about other things the vendor could do.

Both Amazon and the grocery store both keep records on why people return things (and general complaints) and they would be able to track items that people dislike. Amazon already warns you when an item is returned often, for instance. So I'm saying that Amazon can know when someone buys ads for a product that has higher than normal returns and they may have a responsibility there. In general retailers can be held liable for selling defective products even if people want to buy them so I think there's a framework for warning consumers.