Hey, so what if Dan Rather got a little overzealous? We all know that George W. Bush must have received special consideration before getting assigned to the Texas Air National Guard. If the purported "proof" happens to be faulty, it's nothing worse than "lying for justice". (the cite is a comment which appears to have been intended for the next post, so read it for context).
Here's another example of this phenomenon. But no more - I don't have all day.
As the old lefty saying goes "truth is whatever serves the revolution." For the full flavor, read Whittaker Chambers' book "Witness".