In your second paragraph, the two reasons you stated to have kids are entirely selfish. Then you say not having kids is selfish?
I offered two reasons I personally may regret not having children. I could list several others such as the pure joy of watching them grow into adults and mimic you and your partner. If you want to say that’s selfish, to bring another human into the word to experience a universe of emotion you’d otherwise never experience, I understand that perspective. No argument.
But then I offered that choosing to prioritize your own life is in and of itself a selfish act. It’s more explicitly about you than it is about another person.
Would you disagree that going out to eat by yourself is more of a selfish act than inviting a friend to eat out with you? Sharing an experience is less selfish, no?