Except many of those stores haven't fostered distrust in their market place with fake products. I found myself buying Amazon basics because I felt like I could trust them in ways I couldn't trust anything else on the site.
Are you saying you got counterfeit Amazon Basics products? I'm pretty sure Amazon Basics items are only stocked and sold by Amazon and not any of their "marketplace" fronts so I don't see how you would have got fakes.
Amazon Basics is just like the grocery store brands that have become popular. They're basically rebranded products by a different company at a cheaper price with some level of quality endorsed by the retailer (Amazon, Costco, Kroger/Publix grocery stores, etc)
He's saying Amazon allows fake selling of product on their store which erases user's trust in other sellers.
Then Amazon comes up with Amazon Basics brand through which you only get genuine products.
And guess what is reinforced in users mind? That Amazon Basics is only true source of legit stuff rest all businesses selling on Amazon are fraudsters.
Who profits from allowing fake on their store? Amazon.
Amazon's problem with fake products means trust in non-Amazon sellers is lessened which gives the Amazon Basic products an advantage.
Like if I was to go to a brick and mortar store and there was a 10% chance that the brand name cereal I bought could be counterfeit but a 0% chance if I bought the store brand.