Isn’t it Amazon’s job to do due diligence that sellers aren’t committing outright fraud on their platform? I’m not sure what you mean by “allowed”, but I would have zero problem doing exactly the same to Amazon ethically given they actively, on purpose, create this problem in the first place.

Doing something like this is the only way to effect any sort of change anyway. It’s not like regulators are particularly interested in solving this problem. And clearly neither is Amazon. So maybe enough returns where they have to eat the cost will actually motivate them to enact some change.