There are selfish people who are single.
There are selfish people who happen to be parents.
But if you question the behaviour of SOME of those parents, sooner or later you are met with a cry of 'Child haters'

No one wants to be thought of as a child hater, so it effectively stifles opposing views.

But it seems perfectly acceptable to make very sweeping, insulting (and condescending) statements about those without kids.

I do think it's very sad how polarised views are becoming between parents and non-parents. It never used to be like this...I wonder why things have changed so much. Surely we all want a comfortable, hassle-free journey on public transport and I certainly always try and show consideration to others.