I would suppose then, if this explanation holds true, that cold water shaving is harder on an edge than hot water shaving? From what I understand cold water is making hair more "brittle", thus allowing the edge to bite into it easier.

I think though that edges are a lot tougher than some people give them credit for. You're going to have to do something serious to really hurt an edge to the point where stropping or a quick couple laps on a barber's hone wont make the edge right again.