As for the other two, perhaps I should specify: I believe that this is true specifically for people who openly proclaim childlessness as their free choice, who defend it as a superior option, and who counter-attack and try to de-normalise having kids. People in other words who flaunt childlessness and try to pretend that having kids is not really an important issue. All of the people I have met who act in this manner have been strange, warped people. One lady told me she couldn't stand the idea of an "alien parasite growing inside of her." Others I have met scream about the horrors of childbirth, or the disgusting, pathetic and needy nature of babies. None of them seemed to have enough love in their hearts to care selflessly and unquestioningly for another human being, and all seemed to be gripped by pretty nasty self-loathing fears of their own humanity/mortality.

On the other hand, I am sure there are many people who for whatever reason miss on out on having kids or choose not to for decent reasons, but maintain good perspective about their decision/fate, and feel a measure of quiet regret and curiosity about the road not taken, which helps keeps them soft and human.