Well, out of curiosity, how would you guys suggest handling a situation like this OP?
I don't think my approach has been terribly effective, but I did greatly enjoy it.
I'm not really sure what Derek would have done, probably something more chill.
Insulting the guy was what most people would have done, and I don't think many people here have a problem with this. This is the part about the lack of people supporting the game which is more annoying to us since (I hope so) most of the people posting here have bought the game. It is not that bad, but it can piss off people which take things too personal. But you're right to be pissed off, I can't understand why people would pirate an indie game, but I can believe it. But this thread... wow, I just can't believe this guy. He is the embodiement of the word "loser".
I think, maybe for the next game (and I really hope you will earn enough to make one), you should restrict some sections of the forums, let's say, the strategy, mod and support sections, to people who have bought the game (giving unique forum usernames and passwords with the game, maybe...). At least this way pirates would not be getting support from you and from the owners of legitimate copies. It does not help selling, but at least it could help your mood knowing your helping only people who really appreciate what you do.