Having two young kids myself, I understand the situation from both perspectives. I fly a lot of business and yes noisy kids would disturb me too. It is up to the parents to try and control the behaviour of their kids on the flight. However, sometimes, you can’t always control a crying/upset baby and if I was the parent I would feel highly embarassed.
However it should also be appreciated that kids over the age of 2 have to pay for their tickets… so a business class fare for a 2 year old is often full fare, even using miles its the same as an adult.
As some people have said, they deserve to be in business more than the children. However, the children may have paid the same amount for their flights… so they don’t deserve a place in business class ? The airlines need the money and gladly take it.