It's journalism, and therefore it's about selling a story. And a basic principle is that if you can dress up a point of view to sound controversial, or emotive, you are likely to engage with a wider audience than if you don't. The response on here exemplifies that: the article is being talked about= Result for the writer.
Fwiw I think the article raises some valid points, as has been stated here already. Motherhood is not a job, it's a role and a hugely important one, as is fatherhood. I also agree that the deification of motherhood marginalises fathers, and that's not good for anyone, least of all children.
But that's as far as any value in the article goes for me. The whole issue of SAHM / WOHM just seems like a cheap attempt to link the premise of the article to a totally different issue.
Some children have mums and dads who both work outside the home, some have one parent who works, some have neither parents who works. These facts in themselves tell us nothing about the quality of parenting or the relationship between child and parent.