In fact, what encourages bad behaviour is lack of consequences. This is easily avoided by having mechanisms that enable pseudonyms to build up (or lose) reputation.
One of the great benefits of the internet is that as online characters we can be abstracted from matters of sex or race or age. Discrimination is instinctive in huamns, but we can help each other by removing irrelevant signifiers and deal with each other as our actions and our arguments deserve. Why would we want to lose that by signing our posts with an identifier that was forced onto us by others and over which we have so little control?
I believe everyone has the right to construct (and reconstruct) their own identity as they wish. Power over what you reveal to others and how you reveal it seems to me to be one of the more fundamental rights. To force people to use their 'real name' i.e. a name that has been assigned to them by a government organisation is at once creepy and ignorant of the fact that my 'real' name is actually however I choose to be known.