I’ve been a scout leader myself, and I don’t agree with you at all. Its the government that locks the gates and lets the roads fall into disrepair. Not the parents. And if your kids parents don’t get it you need to educate them. Yeah there are lions and tigers and bears out there in the real world. Snakes, too.
As I say, I've never had a problem finding places to camp. And every time I've called the Department of Conservation/Natural Resources in any State (Illinois, Wisconsin, Indiana and Michigan) I've had nothing but the highest level of cooperation. No problems with roads, no problems with locked gates. Lots of places for kids to see and hear some wildlife.
I've never wanted to go anywhere that I'd like to take Scouts to that I've been locked out of or that I've had access problems to.
Educating my parents is the biggest problem. They don't want to listen - actually, the problem is that most of the fathers don't even come to the meetings when I have asked parents to show up, and a significant fraction of the mothers think that I am obviously crazy to want to take their kid rock climbing/white water rafting/away from home for a week into the woods.