A generalization? Absolutely. But if she weren't part of some kind of norm, the initial FA would not have told her that she could take a second seat on an overbooked flight. Of course both the FA and mother could have been isolated cases.
If we are blessed to have children, we will do what our parents did when we were growing up. We didn't fly until we were old enough to know how to behave in public. Age 6 or so.
I won't put a baby through the ordeal of flying.