It may be worthwhile to separate general goods and evils from specific opportunities. The protections you list make children safer from things that are bad for everyone - violence, poor health, inability to get educated. These are, arguably, things that everyone should be more protected from. Saying that children have more of these protections than adults says something about the inadequacy of protection for adults - this sort of intuition drives the affection many people have for universal health care, for instance. Meanwhile, what adults have that children don't are opportunities to pursue things that they specifically find good and desirable. A child gets an education, but can't choose its content except in fairly trivial ways - apart from picking a foreign language and a music class, and testing into certain higher-level academic courses, I didn't get real course selection until college, where I was treated as an adult and had much more loose requirements to fill. As adults, we might or might not have access to education, but if we do, we can pick what kind.

So basically, the protections children get are nice and well-motivated, but they're one-size-fits-all and poorly suited as a substitute for adult freedom to children with personalities.