I think for most people this is an example of Conference Camaraderie (a phrase I am now looking to trademark).
While Big XII teams, and especially Big 8 teams, may be our bitter rivals in conference play, when it comes to intraconference play -- national postseason matches in particular -- there's no question that I'm going to root for them. At that point they are representing the quality and class of the other eleven teams, and their success is linked to the recognition of the others. I hold a high level of respect for the teams in the conference, and Kansas is probably at the top of that list.
Not that it keeps me from grilling my
KU friends. Although it's been a couple of seasons since they didn't have a good comeback.