At the very least, if you're trying to persuade to have kids, people who have chosen to not have kids, those people are not childless, they are child free. Their will is to be without child. They are not failing at having kids, they are succeeding at not having them.

I am dubious of your intermediate and final claims. For something to be necessary, it means that one cannot go without it. Is procreation a biological imperative, with strong positive reinforcement from the individual's biological feedbacks? Sure. But is it necessary? Strictly, no.

I don't think you can make the claim that someone saying it is not necessary is inherently biased. To claim that procreation is not strictly necessary is a neutral, objectively true position. The bias in the perspective of "child-free" is the implied framing of the lack of procreation as a personal or moral good. Procreation is, again, unnecessary, and is (in many ways literally) a burden. Whether one frames that unnecessary burden as positive or negative is at issue here.

I don't appreciate the claim that people must be biased in order to observe simple facts, denuded of emotion.