I am a custodial parent who had to petition to move and fight a big fight to move and it was only 41 miles away

Why? Because the other parent was a jerk and wanted to waste taxpayers money and mine to try to make it seem like I was creating distance.
On the other hand my childs father moved all over the country and when he decided to show up and be a parent, I let him without a fight. Why? Because it's about the child after all. A child has a right to both parents unless they are in danger from one of them.
You are asking why SOME NCPs raise a stink when the CP moves- well, not all of them do. You are also asking why a CP can't move without the NCPs consent. These are obvious answers to me, and I'm not a lawyer! Some parents are jerks! CP or NCP both. Some parents are not jerks and want to do their best to allow access to the other parent. So you making sweeping statements that could go either way and yet demand explanations!
The same father who fought me about moving 41 miles away wouldn't find himself in the same fight if he moved anywhere he wanted to. Is it fair? No. Is it one-sided? Yes. BUT that doesn't mean I have to stoop to his level.
Pretty simple, do what's best for your child and stop trying to control the other parent's life.
Sounds like you had a bad experience with this topic- well, so did I. But that doesn't mean I can now assume that EVERY NCP is an idiot bent on making life difficult for the CP. (just the one I picked, I guess!

) lol