[meritt]

Amazon ships products from their warehouses, in their packaging, charges credit cards as "Amazon.com", provides customer support, and accepts product returns. This makes it generally indistinguishable to the consumer if they're purchasing from Amazon or a sketchy third party vendor, as simply the "best" deal gets populated into the buy box. Unless a consumer drills down into the full offer list, the specific 3rd party merchant and the corresponding ratings are completely hidden.

That's significantly different from someone running their own ecommerce site where they are very clearly the merchant of record.