The legal difference underlying the lawsuit between this behavior by Amazon and the behavior you raise by those stores is not the behavior, but its context.
Amazon, the complaint alleges, has durable monopolies in two relevant markets which the behavior leverages and reinforces, making it a means of illegally maintaining a monopoly.
The other stores do not have monopolies, so the behavior is not part of a system of illegally maintaining a monopoly.
This is very similar to the kind of discussion that happened at the time of the Microsoft antitrusts suit about bundling software: one of the ways Microsoft illegally leveraged their Windows monopoly – in this case to monopolize other markets rather than to maintain the Windows monopoly, but same kind of issue – was bundling IE with Windows. People made all kinds of “well, how is this different than maker A bundling software X with software Y”, and mostly it wasn’t, except that maker A didn’t have and thus wasn’t leveraging a monopoly in the market of software X, so them bundling software Y with it wasn’t an issue.
“That's absurd” is an inadequate rebuttal to pp. 39-71 of the complaint detailing the basis for thr claim Amazon has durable market power in two relevant markers.
Anti-trust rules cover both, with a (difficult to apply, but relatively well-developed) concept of “monopoly” which ultimately boils down to whether or not substitution happens in practice rather than whether there is exactly one firm ina descriptive market. There's no need to “move away” from one to the other.
https://www.ftc.gov/advice-guidance/competition-guidance/gui...
This is false. The Kirkland Signature versions are just the white-label version of one of the brands that are sold in Costco. For example, the Kirkland batteries are white-labeled Duracells; the Duracells are frequently sold right next to the Kirkland ones. The KS coconut water is just white-labeled Vita Coco and is sold right next to the VC coconut water. The point of the white-label product is to segment the market: the higher price of the branded version will make it seem like a more premium product while cost-conscious customers will purchase the white-label brand. Either way, the manufacturer gets paid.
At a Costco, they'll often stop selling the brand name product if they introduce a "Kirkland Signature" version. Amazon doesn't take down competing products when they launch Amazon Basics versions.
Not really intending to defend Amazon, because they are indefensible, but by big corporate standards, I don't see how they are anywhere near as bad as Walmart. And nobody is trying to break Walmart up.