You shouldn't. If you don't feel the overwhelming need to have children, you probably shouldn't.
I wanted to have children from when I was about 10. I knew that it would be the most important thing I was to do with my life, and that's how it's turned out.
FWIW I don't know a single parent who would say that it's not absolutely awesome to be a parent. Maybe I don't know many bad parents...
> "And marriage can only be good if the parents know and acknowledge that they together go first, kids come second. Period."
That's a terribly sad outlook. Your children are extensions of yourself. They should come first forever. They're not pets that you just take in and look after. They're your babies...
I don't know if you have kids or not, maybe you don't have very strong parental feelings :/