I don't think this is necessarily true. People may be quite willing to be uncivil to "Martin Carpenter" as well... after all that's one of the points of 'doxxing' someone on a forum, to humiliate them with their real identity, and troll their real-life friends and family.
Plus, how are you going to tell whether "KRapp" is my real name, a derivation of my real name or my account name is just a pseudonym that corresponds with a real name? You could guess it from my email or my facebook account. In my case (and probably most cases) it's quite easy, but if you're serious about using real names, I think you're still adding some minimal effort on your part to have to validate them.
Maybe my real email is "somethingotherthanmyname@gmail" and my real name just happens to be "Jango Fett." How 'real' does a name have to appear? Google's already running into problems trying to enforce this, and they already have all the data, because 'real names' don't necessarily map as logically as people assume.