Now that the two have merged irrevocably, I'll concede that you need to reconcile the ability to reach anyone anywhere at any time, with almost no reprecussion, with the fact that people are dicks.
I think there might be value in the reverse though. An online community that actively prevents people from posting personal details. E.g. you enter your real-life details, and you're prevented from revealing them to someone, and people can't post addresses, real names, etc. You can make as many accounts as you want, but they're all tied to a specific real identity, so if you start harassing someone, you can be blocked and you can't make a real new account. An effort to have your cake and eat it too - keep what made online communities great (anonymous communication and the ability to discuss things of any nature with consenting partners, without jeopardising your real life), while avoiding the problems that trolls bring.
Cuts both ways.
I used to run an online community in the late 90s early 2000s which would now be called a social network. Some people used real names, some people used pseudonyms, and some people used both. There was no "disaster".
For twitter, people don't need to know who the persistent abusers are on their government ID, only that there are rules and they will be effectively banned if the rules are broken. De-anonymisation enables random mobs to apply "accountability" through death threats offline. For some people this is a serious risk.
(Or in CS101: authentication and authorisation are not the same thing)
Welcome to the human race! You are probably not going to enjoy the orientation period.
Bob can have whatever name they want. They don't get to threaten to rape and murder another user.
If you limit yourself to three-part 'normal' names, there may be some matches, but if everybody knows user names are doled out randomly, I don't think that matters.
For the Facebooks of the world, I doubt using pseudonyms matters, though, as they will soon discover who's behind each pseudonym, even if a third party assigned them, if only because your alias will be in the address book of your friends.