I think a lot of it has to do with one word..."hope".
If you remember Joel Buschbaum reported when Henson left to play baseball that he, (Buschbaum), surveyed several GMs at the time and the vast majority of them said they would have taken Henson over Vick with the #1 pick in the draft. That's the kind of potential he showed in College.
So, several years later here we sit without our young, franchise QB like Manning, Brady, Rothlisberger, Palmer, etc. and the only player we have on the roster at the QB position who had the College hype those guys had is Henson. (I'm not counting Bledsoe, of course, simply because of his age and the limited number of years he has left to play).
If we were to acquire the next Aikman, Brady or Palmer and that guy stepped up and showed he was the future, you would see the love and infatuation for Henson die pretty quickly. I say that and I'm a Henson supporter. That's just the way it is as a fan. I simply want us to acquire the next great Cowboy QB.