... then you might want to make that more obvious. There's no indication that the game is about piracy from the title, and the statement doesn't come across as a joke, it comes across as one of those typical piracy warnings/admonishments.
I'm not sure how you found it funny.
I'm slightly concerned it may just have been a misunderstanding, when someone else told them they need to activate their Steam key for Itch's DRM to work they responded "See the author's reply" you didn't seem to have replied anything related to that, so I wonder if they misunderstood what I said, which was "It's a joke, because the game is about piracy...", not referring to the message, but to my earlier message saying "Sounds right." when they mentioned the message, and somehow they mistook me for the author and mistook my message for the message itself being an intentional joke?
Could well be wrong, but the situation just seems off and I'd hate for this to have been a genuine innocent misunderstanding.