Except for Google search+product combo, in every other example you cited there is a contractual relation between the product and the SM. If I have a product pa

Except for Google search+product combo, in every other example you cited there is a contractual relation between the product and the SM. If I have a product page on Facebook, I have a contract with Facebook. Facebook could choose to end that contract with me and close my account. But Google News blocking/downranking a news site does not involve any contract ending between Google News and the news site. If I don't have a product page on Facebook, Facebook could still choose to block/downrank posts where users on their own free will mention my product. But I don't think this really happens at any significant scale yet. Same applies your Amazon/Ebay/Youtube/Twitch examples.