To begin with, the physical world doesn't have a single standard of ethical or moral behavior, as it varies subtly or greatly by jurisdiction.

The Internet doesn't really have the same territorial boundaries that are presently vital to the functioning of humans in the physical world, either. Of course there has been some legislation on the matter and many have tried to assert jurisdictional power (famously in file sharing cases), but those are all highly volatile concepts.

Indeed, each site chooses its own specific rules and guidelines. They're globally accessible, ad-hoc jurisdictions in of themselves, in many ways.

Finally, the web application platforms themselves are not entirely blameless. They've created highly gamified, bizarro worlds where people are signaled and conditioned to engage in forced and obnoxious "social" behavior that many would consider totally histrionic and narcissistic if done in the physical world. The need to post every picture, to post every vapid thought in a global public bazaar... most humans simply aren't used to such a thing, and evidently cannot cope with the repercussions of it, either.

Governing behavior on the Internet is doomed to end in an ambiguous mess without enacting ID laws that would subvert its purpose.