I have no problem with people who want to be childless. Honestly, there are some people who should just not have children. I only get mad at people who assume that all children are little monsters. In one restaurant years ago a lady saw my 8 month old son at our table and loudly complained about "not another baby". Except for a few giggles from him that had other customers smiling he was very well behaved.
You are right, some people don't deserve to be parents.
I know what you mean. One lady actually refused to be seated next to us at a restaurant when we were out with our kids (4, 3, and 5 months at the time). My boys were sitting quietly and eating their food...not at all being obnoxious (I have a cure for that, lol).
She was quite loud about her reason for wanting to be moved, too. Nice lady.