I don't find it difficult to understand how pirating something that isn't made anymore is illegitimate. When you make something, you should have absolute control over who could make copies, change, or distribute it. Piracy robs the creator of their control over what they have made.
Of course, I think many companies are big doo-doo heads for not releasing old games that they're never gonna republish or make money of again as freeware, but they should still be in their full right to do (or not do) whatever they want with what they themselves created (or bought the rights for).
Laws that give the creator absolute control over their creations must stay in place. However, I think many companies should show some goodwill when it comes to old games that will never earn them money again, but this must be up to each company/developer/publisher/whatever.