There are plenty of reasons to be anonymous online. There's plenty of reasons not to be. I kind of wish that the government would launch a series of public political debate forums that required real ID, not that I think they would actually be valuable places for debate, but the technical challenges would be worthwhile to solve and the ability to publicly register debate positions would be incredibly useful for nailing politicians down.

The problem comes when the government tries to regulate one form or another, because strongly authenticated, pseudonymous, and anonymous forums all have their place in debate, and there's reasons for both public and private entities to host all three.