I think this is just a case of mutual ignorance rather than evil.
I am of the belief that Gamestop makes money off this ignorance on purpose. Not sure this is some real evil here with a plot to create a bargin bin of used game titles. However, Gamestop is run mostly by employees who are game fanatics but aren't able to do much else, with a number of customers who are clueless but buying stuff for hardcore videogame fanatics. And they create a cycle that is meant to lock yourself into there. Of course, with this, one can end up getting a range of experiences.