One side of me "knows" that piracy is bad because I take something (or copy it rather (nothing is technically "taken" since nothing is removed but merely copied)), and while I will sometimes pirate newer games just to save money, I am all for pirating older games that are going skyhigh on eBay, whether it is morally right or not. If a let's play made me curious about a 25 year old game that goes for 1200DKK on eBay, should I then shell out that money just to check it out? No, that's ludicruis money for ANY game! If I absolutely MUST have it for my collection, then sure, you do you with your own money. But if you just want to check the game out and see what you missed those 25 years ago... pirate that shit, no one who made the game cares anyway.
Besides, they say that some 70% of all games are lost media, because some companies don't care. Well in those cases I see piracy as not only the only way to preserve those games, but to spread them as well and make them more widely known.
You could say; "Well you don't hold the rights to that game so no matter your intensions you have no right to pirate it. If the developers have no interest in preserving it, then that's their right."
But to that I say that the moment you release something to the world, it becomes part of our collective culture, and culture isn't owned by one lone individual. So the moment you make a work of art (like games are) you don't have the exclusive right to say "don't preserve this".
Art is part of our culture, our history, and our identity, and again no one individual owns those three things.