It's possible we're not on the same page on what you meant, but after your clarifying, it still requires defining what a "bad product" is, and that's not as easy as it feels like you're suggesting. A cheap product can be both good value and a bad product, depending on the type of product/intended use/customer expectations/etc. But it's up to the customer to decide that.

The main point I'm trying to make there is that customers are unpredictable (and irrational) and they have autonomy, and they need to bear at least some responsibility in making sure what they are buying meets their needs/wants, regardless of what Amazon was paid to suggest to them. 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. That's essentially what Amazon is doing and what the complaint is.

> you implied that there was no knowable standard for good value

This is something I stand by (see above), but you would have to take it to an absurd extreme to conclude that it means I think people are happy being scammed.

Being scammed on Amazon a separate problem, with other avenues of recourse (filing complaints directly to Amazon/requesting refunds, legal system for counterfeits or misleading advertising, etc.), and Amazon is financially incentivized to avoid it to keep customers happy/returning.

> 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.

It's not that unknowable. When a customer makes a deliberate tradeoff that's fine. But some products are strictly worse than others. You can build a pareto front out of features and price and see which products are near it and which are way behind.