Sometimes people espouse selfish, self serving policies and beliefs. However, people rarely like to admit that they are espousing beliefs which others might find selfish or even immoral; and so, people do mental summersaults to convince themselves that their behavior is appropriate and moral, even in cases where it obviously isn't.
This behavior is not limited to small things. Even in very big cases, dealing with issues which should be clear and absolute, people do this. Racists in the United States, for example, worked very hard to explain why it was better for everyone that the races stay separate, that blacks not congregate with whites, and so forth; they didn't just espouse those beliefs, they actually convinced themselves that their behavior was the moral, right thing to do. Mixing of races was not natural, violence would erupt, and so to keep everyone safe we needed to make sure everyone was kept apart.
In comparison to that monumental feat, convincing yourself that it's fair and right to eliminate sales of used video games is a miniscule achievement of the human psyche.