The blame should be put squarely on the shoulders of tophatter.com. They know the quality of what is being sold and choose to look the other way for the sake of making commission and sales fees on these imitation goods. In my estimation and also the interpretation of the law this is outright FRAUD.
Inverse operations are opposite operations that undo each other. Addition and subtraction are inverse operations. Multiplication and division are inverse operations.
But there is one in Photoshop. And it exists independently of the backstepping that you can do in the History palette. Which exists independently of the back-to-start Revert command. Which means you can undo History and backstep Revert and revert Undo, not to mention undo the backstepping and, well, you get the idea.