Outrage is not the blinding emotion that rage is. Outrage has the moral component that rage lacks. Rage blinds us with hatred and raw emotionality and often seems like a knee-jerk reaction.
Outrage has an intellectual component that, IMHO, allows the rational part of the self to keep the control needed so that one does not fight blindly - as in a "blind rage."
I hope this makes sense - you hit a real chord with me and it was difficult to put into words...