Parenting, according to Gru, is a simple process. Take care of basic needs: "food, water, poo poo & pee pee". Take care of intellectual needs: basic education (dance class). Take care of higher needs: recreation and emotional bonding. Despite himself, he gets the childcare right -- a textbook Hierarchy of Needs met to Maslow's specifications.
Gru has no plans "for their good". On the contrary, his plans are entirely self-serving. His adopted orphans are simply a means to an end. Their safety and well-being are taken at the basic minimum standards, knowing that he can dispose of them when they have fulfilled his requirements of them. How heinous.
Why do we face a declining fertility rate in our country and in many other developed nations around the world? Because we want to be good parents. Gru is a monster in his regard for childcare principles, but he's got three kids while the rest of us have... significantly less.
As good parents, we place our kids first above all, ourselves included. We plan far ahead into their future, shape them according to what we have determined is best for them, and raise them like we're never going to let them go. We know about hygiene and health, about discipline do's and don't's, about child psychology and labels like ADHD and OCD which we identify in children and lament how we have failed them somewhere, somehow.
Our modern model of childcare looks really good. We've taken care of every aspect of child-rearing that practically guarantees healthy, happy kids that will grow into healthy, happy adults. Now, if only we had some kids to work our plans on.