First off it sound like you are more annoyed by the parents than the children.
I never wanted kids, and neither did my husband. We felt it would be wrong to add to overpopulation, and it would be unkind to the child to put it through Whatever crap is coming in their lifetime.
But despite precautions, I got pregnant at 33. We talked about options, and decided to just have the one. I had my tubes tied about 30 minutes after my daughter was born, so she is all there will be for us.
My point here being you never know what circumstances will come along and possibly change your mind.
I also barely tolerate most parents, and am Pratt critical of most of the ones I see (around here we have a lot of evangelists.... talk about raising kids wrong in every way!).
I also still don't much like very little kids. I had a hard time loving my own until she was about 3 or 4, hard as that is to admit. I had severe post partum, possibly boarding on psychosis for the first 6 months to a year until I got treatment. But I love children in the 6 to 12 year old age range, and volunteer to work with them and help whenever I can. But baby's....no. I do not like baby's and toddlers, they are destructive and they make me very uncomfortable.
I also find it funny but true that atheists tend to have 1/3 the children of religious. The correlation also holds true with educated vs uneducated. So the dumb religious people will keep outbreeding the intellectuals, we are dooming ourselves to idiocracy.