> Adults are just as vulnerable to copying poor behavior as minors.

Adults can be vulnerable, but I don't think just as vulnerable. Youngsters with no initial idea of how a given thing works have nothing with which to compare and contrast and potentially reject the first idea presented to them. Generally, the younger, the more impressionable.

> Remove stigma associated with sexuality. [...] Most people probably wouldn't even go to porn sites if they could just watch something steamy on Netflix.

I do agree with loosening the stigma. If there are parents that are giving their children unrestricted access to the internet, and those children may expose things to others that have better parental controls, then the straightforward solution is to have some form of earlier sex-ed. Doesn't need to cover everything, but enough to prepare them against the bad influences they'll apparently encounter. "Something steamy on Netflix" may be a positive counterexample to help them reject nonsense fantasies on porn sites.