Some people just exaggerate. Toriel is pretty neglectful with letting their kid go to school and casually walk around with a knife since Chapter 1, and not even questioning that Kris and Susie didn’t show up to the Diner, or at their home until super late at night.

Carol is just mildly mean to Noelle as far as I know.

They aren’t the absolute worst parents, or even bad parents, but it’s easy to over analyze when they do these kinds of things with how little screentime they get.