I agree with Beagle that there should be an expectation of peace and quiet when travelling but, on the other hand, as has been said before, small children, particularly babies, only have one way of communicating. And that is noisy!Changes in pressure can affect their ears, just as it does to adults, and that discomfort can trigger distress. So, circumstances can be outside parents control.
What will be more distressing is the day passengers are allowed to use mobile phones on aircraft! That will be more noisy and intrusive than any distressed minor!