I'm sorry, but I find this quite a weak argument. If Benghazi had fallen to Qaddafi, there's no way of telling what could have happened. A humanitarian intervention quite clearly was called for when it became clear that the fall of Benghazi was imminent, certainly when combined with some of the Qaddafi-rhetoric.
Again, I didn't oppose an idea of humanitarian intervention upon the UN mandate. Preferably to create a stealmate, that would separate the two sides from each other.
Sadly, instead of this, we have NATO supporting one side of the civil war against another, which I consider a mistake.