I was allowed to walk to and from school by myself every day. Not only that I spent a great deal of time not under my parent's gaze. In fact most people are raised outside of this situation you are imagining.
You are calling basically everybody a bad parent and that isn't the case.
Letting your children walk to and from school is one thing (I did this, my children do this too). Not noticing radical mood swings (and likely mental disorders) of your child is another thing - one that, in all honesty, doesn't qualify you as "good parent", at all.
Not at all, I’m calling a bad parent anybody whose kid is getting abused repeatedly without the parent realizing it and intervening to stop it. Well, not a bad parent, a beyond awful parent.
You are calling basically everybody a bad parent and that isn't the case.