How are the two related?

A user obtains the game through legitimate means by "buying" the game. However, they do not own the game, and are in fact, just renting something. This is despite decades and decades of game buying, especially pre-Internet, equating to owning the game and being able to play the game forever, even 100 years from now.

By pirating the game, a user has clawed back the implied social construct that existed for decades past: Acquiring a game through piracy means that you own the game. You have it in a static form that cannot be taken away from you. There's still the case of server shutdowns, like this legal case is arguing. But, unlike the "buyer", the game cannot suddenly disappear from a game's store or be forcefully uninstalled from your PC. You own it. You have the files. They cannot take that away from you.

The phrase essentially means: You have removed my means of owning software, therefore piracy is the only choice I have to own this game. It's not stealing because it's the only way to hold on to it forever. You know, because that's what fucking "buying" was supposed to mean.