[arp242]

Selfish or otherwise unpleasant people can be found in any demographic: childless people, people with children, people over 1.80m, people under 1.80m, etc.

Some demographics certainly have higher ratios of unpleasant people. In some demographics it's even close to 100% (e.g. neo-Nazis).

It's entirely unclear to me if the rates are different for people without children. If they are, then you really need to do better than this kind of armchair analysis that you've posted here.