Actually, they do that. I’m a part of parenting groups and some mother posted that she voiced thoughts of hurting the baby and had PPD, and she was forcibly separated from her baby for evaluation and treatment for a few days.

So yes they did in fact temporarily “get rid” of the mother for just voicing such desires, never mind having actually attacked the kid like the cat did. The mother said she was traumatized by the separation but commenters, especially people working in child protection, assured her that it was much better than a permanently injured or dead baby.

In the long run having a mother is much more important than keeping the pet, which is why we want mothers to return to their babies when they’re better.

But what you describe absolutely happens.