dunno if anyone said these yet but, little white lie and half truth
I don't think those qualify as euphemisms, Matt, let alone evil ones. There IS such a thing as truth mixed into lies to make a complex and plausible falsehood, and deceptions that prevent evil.
The character of "child-free", on the other hand, besides being used to directly approve of abortion and a life without children, has the general effect of producing a generation of adult children, who do not themselves grow up.
On the whole, for most people, (excepting monastics and a small minority actually called to the single life) children are necessary and salutary. They force us to put what we want for ourselves onto back-burners,pull us outside of ourselves and force us to love someone else. They teach us what we must look like before God, by disobeying and misbehaving and disappointing us, as well as by the precious things they do that make us love them all the more.
It is (again, for most people) by living a life of adult irresponsibility, where the responsibility of children is perennially absent, where, upon meeting the obligations of work and paying one's bills, one simply... lives as they wish, and discos, partying, cinemas, gaming, etc become primary and regular activities rather than exceptional ones as they must be for parents, that a generation of adult children has grown up, that cannot conceive of other than what the self, the individual wants, and so we hear justification for social tolerance of all sorts of evils, from openly available inappropriate contentography, violent video games, and a laissez-faire attitude towards public behavior, something which children of parents, conscious of the necessity of protecting their own children at least, tend to oppose.
So the traditional "childless" is accurate and appropriate, and "child-free" merely approves of that "choice" to remain irresponsible, to buck tradition, refuse committed marriage for life and the natural product of normal marriage - children - in favor of what the self wants. As they say, why buy a cow if milk is so cheap? And so,it really is a euphemism that supports the abnormal, wrong and evil, even though its users do not intend to do so as a rule (as with all evil euphemisms).
Again, if you have not read the essay that launched this thread, I highly encourage you to do so.