I totally agree that "selfish" seems like the wrong word to describe people who don't want to have kids -- whatever their reasons. Even if those reasons have to do with keeping their own interests a top priority. Maybe they want to focus on their careers, maybe they want to come home from work and have time to themselves, maybe they want to be free to go where they want, when they want, unencumbered ... and so on. Those reasons are self-oriented, I guess, but I don't consider them "selfish" in the pejorative sense we usually use that word, meaning "greedy" and "uncharitable."
I think part of the problem is that our culture so frowns on placing a priority on one's own interests that there's no neutral word for that.
I'm speaking here of people who opt not to have kids. People who've already had kids and then decide they don't want them ... well, that becomes trickier. I don't know what the right word is to describe them -- it depends on their individual circumstances -- but they've certainly made a big mistake.
But I haven't read the original article yet. Are we talking about a mother who wants nothing to do with her kids? That's problematic. Or is this a mother who simply doesn't want live-in custody of them -- which is a totally different thing? I've written about mothers in the latter situation. Most of them make the decision for their kids' sake. Some regret it; some don't. But it's very hard on them because they're so harshly judged for something that fathers do all the time.