I get your point MDT, but the more I think about it the conference affiliation is only one part of this, and probably not the main part.
You see, I have lots of Texas friends, and this board is just the tip of that iceberg. I lived in Texas for 6 years and still stay in touch with several friends from that time (I was in my 20s after all), one of my degrees is actually from a UT school (UTD), plus several family members have various UT degrees, including some from Austin, etc. So, while I'm not really what you might call cross-bred, still yet I have a lot of sympathy for my friends and family members who bleed burnt orange.
When I cheer for Texas in a bowl, I'm mostly cheering for my friends who are Texas fans. I'm cheering for a few family members who live and die by the fate of the Horns. Am I myself actually cheering for UT? Probably not as I've been cheering for Oklahoma since I was knee high to a scissor-tailed flycatcher and they were always the arch foe.
No, it's not for me, but I'm just happy for all my Texas friends and family when they're happy. And Texas is in the same conference these days, and lord knows the Big 12 needs all the help it can get.