That is a batshit response from the manager (screaming leads to other children drowning, they apparently don’t have enough lifeguards for the number of pools, but despite that every other hotel in the Philippines has had multiple guest drownings while they haven’t, and also Covid?).
The hotel also sounds completely miserable, and seems like staff and guests alike have a stick up their arses. I wouldn’t have stayed there pre-children, and I am extremely quiet myself.
But yes, the website and policies are very clear, and she was misguided to book that specific hotel. Possibly English is not the mother’s first language, but that review makes her sounds insufferable too.
I’d say you were well out of it, honestly.