What’s missing here? Any mention of a curse. Sianis never cursed the Cubs for his ejection. Why would he? He was a Cub fan and his customers were Cub fans. If your whole point for being at the game was to get publicity for your tavern, why would you ever want to be linked to cursing your customer’s favorite team?
After the Cubs lost Game Seven of the Series in Detroit, Sianis did send Phillip K. Wrigley a telegram that said “WHO SMELLS NOW?” That got him another mention in the newspapers. That’s the closest he ever came to a curse.