To have children or not?

Another one on having kids, but this one talks about the fact that many people (married or single) who don't have children and don't want any or EXTREMELY hostile towards those who do. I understand that some people don't want kids or are better off not having them, but I don't understand their anger towards children and the choice to have them. They were once a child themself, and if their parents had decided not to have children, THEY wouldn't be here!

An excerpt that makes a good point:

In our society parents do a wonderful job of portraying the difficulties of having children: the financial burdens, the time drain, the guilt, the exhaustion. But we do a lousy job of getting across something else about parenthood: It's fun! When you are experiencing parenthood from the inside, there is an overwhelming pleasure in the funny, fascinating things your children do. When my daughter was 2, she put her arms around me as I was kissing her goodnight and said to me, "Mommy, you're a wonderful husband." That was better than any of the movies I hadn't been to since she was born.

I've read before the statistics that claim childfree couples have better marriages and are happier people. I think that there are things that are difficult to be measured in a study-and the joy children bring you is one of those things. It's very hard to quantify.
She also makes a good point about the nonparent's ideas about the passage of time. (I would note that this applies to discussions about large families as well. People seem to assume that all the children are babies or childish and their comments reflect this. When you have 17 kids, they aren't all in elementary school!!) I like her ending sentence, it reflects how I feel.