I'm sure the rationale is just like helmet laws. It's there to protect you from yourself. If they penalize everyone who runs a red light enough, they think it will make the idiots who run red lights into crossing traffic think twice. Problem is, those idiots aren't thinking once.
That's probably true. In many areas though, laws and street/traffic patterns are changing in small ways to accomodate the inherent difference of cycling vs. driving a car....with bike boxes, bike lights, center lanes, contraflow lanes, etc. I like seeing this and I think the Idaho stop is a logical candidate for it in many places.