I honestly believe that many people are just genuinely clueless. They don't think about others, or don't travel much in general, or are so focussed on their children that they don't realise that not everyone thinks that they are the most wonderful things on the airplane.

Read FT for example, and you will find many, many parents who think that it is perfectly acceptable to change even poopy diapers in an airline seat.

Or they think that it is fine to allow their precious to zoom around busy LHR T5 on a trunki, and if someone trips over snowflake, it is of course the passenger who is at fault for not being more careful. (No matter that most of us don't expect a child zooming around on an amimal shaped rolling case at ankle height in a busy terminal...)

I suspect that this thread may be taking a trip to another forum here shortly, depending on how it continues, and there may be input from those very people who think that there is nothing wrong with the above.