Ahh but not everybody likes all everything and thus the best of something may not be appreciated and therefore would not add to the quality of a persons life. For instance, to take an example from something much less important than child rearing, I only like red wine, I've always found this funny because I love fish, but I just don't like the wimpy flowery taste of wines that aren't red (on the flip side I LOVE red wine, even the cheap crappy stuff very dangerous afflication). Even the finest of white wines is not to my liking. Thus, were I collecting the best alcohols I would skip the white wines, there'd be no reason I wouldn't enjoy them anyway (though if I were collecting for resale I would get white wines, they'd be safe no way I'd ever open them).
Just because something is the best doesn't mean you'll like it. While for many child rearing is apparently wonderful and enjoyable it isn't for everyone. If we all took the same pleasure from the same things it would be a terribly boring world no need for variety in anything, no catering to individual tastes. Thusly some people love children, have a bunch, maybe teach or do other things involving kids; and some people loathe children and seek to create a child free zone in their personal space. That's just how it is. Maybe it's a flaw, or maybe that's just how things are.
You are equating choice in wine (one's tastes in alcohol) with deciding whether or not to raise children (one of the primary experiences of human life). If you don't find that absurd, I really don't know what to say.