I don't think history supports that. There were essentially zero childrens' rights until post-war. In some locations child abusers were originally prosecuted via animal-protection laws.
The “protect the children” argument has little to do with actual children protection laws. It’s about using pathos of the crowd to manipulate opinion.
Regarding history, I don’t know about the US specifically, but Europeans countries have legal children protections since end of 19th, beginning of 20th centuries (depending on the country).
