I'm not saying anything against not having children, and it's admirable that you've put effort into introspection and came up with what's best for you. I am saying against other people thinking that they have the right to tell others whether they are a fit for parenting. You can suggest, you can point out, you can educate, you can do all of the above - but don't ever decide for others if they're mature enough to make their own decisions. I guess the poem got my guard up exactly for that reason.

But with only flawed models for reference, that is to say 'human beings', I don't believe it's very reasonable to insist or believe that anyone can parent better

I beg to differ - not that we're all aren't flawed, but that you can do a better job than your parents, given enough education and effort on the matter. Being a parent is never easy - unless, of course, you decide to neglect your child, in which case I doubt you can be rightly called a parent in a context other than biological - but then, you're building a future for your child, so I believe the effort is worth. It's not to say that my way of things - flaws included - will not affect my child: they will, even if I try to be a completely different person, in which I'll certainly fail. It's to say that, with enough information, you can negate the negative aspects of your personality or divert your negative energy towards important things (for example, being stern with your child to teach him or her discipline - it requires both love and a certain level of rudeness, of denial of whims which both - and only both - will later lead to a more disciplined person, which, in my view, is better overall).