This is new news?
Amazon has been a predator for years and its well known.
Small mom and pop store uses Amazon, Amazon knows what they sell and if the product is hot. They know their suppliers and their customers who purchase thru Amazon.
Amazon holds the relationship.
Amazon can then decide if they want to also sell the product and because they already have the infrastructure and customer relationship, the can determine how much of their "partner's " biz.
And Amazon can change their prices in real time. For example... if their "partner" has a low inventory, Amazon will know and if the product is hot... they can raise their price so that while they are not the cheapest, when their "partner" runs out... they will have product ready to ship. They would capture margins and the customer doesn't know or care. After all, its Amazon.
If the partner sells direct... go thru them instead of Amazon.
Anon for a good reason.