I'd be surprised if there wasn't more to this story. Warnings first? What exactly were they doing?
That said, with our little one having spent several flights in pods (both on our lap, and now with his own seat) - whenever he made a fuss (very rarely) I would often take him for a walk back to economy. Surprised they didn't proactively do that? It's obvious you are bothering people who have paid to sleep or rest.
It would be nice if they made the mini-cabin the only place for kids on planes that don't have it so we didn't worry about bothering anyone. On a recent flight the crew had us moved from the mini-cabin forward because we were the only ones there... that was the point!