Indeed, the modern concept of childhood being a distinct and uniquely valuable stage of life is fairly recent, owing a lot to Victorian culture and Freudian psychology. Most of the laws specifically focused on protecting children only date back to the late 19th or early 20th centuries. The idea that childhood extends to 18 years old, implying that adolescence is actually part of childhood, is even more recent.

I don't remember the term for it, but some cultural critics have described a more general pattern of certain populations being set aside as "innocents". These people are then to be protected from being "corrupted" by the harsh realities of the sinful world. The flip side of this special status is that they're treated as intrinsically naive and not capable of having meaningful opinions, possibly even on the subject of their own needs and desires.