.... ?? What?
So, people should be able to just steal any product that they don't feel like paying for if they call it a "cultural good", whatever the hell that means.
No. Not to steal anything they don't wanna pay. But it's also unfair to prevent people from enjoying immaterial goods (a program, replicable without any real cost, for instance, or music, movies, and the like... which are all "cultural" goods), just because they cannot afford it. If you work full-time, and have only enough money to pay for the rent and the food, plus some clothes from time to time, well, you're not in a situation where you can put $75 in a game. But if you've got a decent salary, and can afford to pay for a game you enjoy, then yes, piracy ain't "fair use" anymore.
Oh, and as for demos, they usually let taste only a little bit of the game, but do not necessarily allow people to know whether the full experience will be worth it. And, sometimes, games change from the demo to the final release. So the best way to try a game is to use it in the form you're gonna buy if you like it. You can borrow it from a friend (this ain't illegal, as long as your friend doesn't play it while you still have the game), or download it (this is illegal, but is exactly the same, as long as it's done in a "fair use" state-of-mind. Meaning you do buy the game if you like it.