Why do people insist on telling us that gambling is a zero-sum game, in an attempt to sound wise and knowledgeable? Do you really believe the are people who think that a poker game magically creates new money for everyone?
people who insist on saying 'zero-sum' is really just passive-aggressively saying that the person indulging on said activity should've spent their time on other non-zero sum activity.
It's still a hell of a lot of fun though.