If an older game is re-released in the same state that it came out in, then yes, I would say that it is also wrong. If a game is so old that a company either A. has no interest in re releasing it or B. The company is no longer around, or C. New copies of that game are no longer being created than I see no problem with emulating the game, as the company isn't losing money.
If you didn't pirate the game you'd only have a few options of going around playing it either by A. buying it, B. getting a borrowed copy, or C. Buying it second hand.
Of course Piracy isn't stealing in the legal sense, but IMO it is in a moral sense. It's the same thing with most things that fall under copyright infringement. The point is you're getting a product for free that a comapany is selling, without said companies permission.