But are such people breaking the law? To my knowledge, being a douchebag on the internet is not a crime (nor do I think it should be). Could you perhaps point me to one of those posts that explain this in more detail?
If being a douchebag involves defamation, then yes, you can be sued in civil court. This is all going under civil action, not criminal court (big difference).
Remember, broadly speaking, defamation is just undertaking some action that gives some entity a negative image. Before you go nuts on that, yes, truth is a defense against defamation (ie: it is not defamation if it is true). At which point parody becomes defamation is something of a grey line, which Carreon will try his hardest to use.
If Carreon can paint the image in court that the internet is after him, it would probably help him make his case that the fake twitter account is defamation, not mere parody. After all, context matters.