Interesting take.
I grew up in Virginia (Norfolk/Va Beach area.)
My dad was a retired Infantry Sergeant Major who was stationed at Ft Hood Texas in the early 60's. He became a die-hard Cowboys fan while there (he wasn't really a football fan before that, so he didn't have a team.)
I remember, when I was nearly 7 years old and starting to become very interested in football, we were watching the '72 Super Bowl between the Cowboys and the Dolphins.
Before the game, my dad looked and me and ,"We're Cowboys fans in this house, so you best be rooting for the 'Boys today." I've been a Cowboys fan ever since. (apply Infantry CSM steroetypes here, too:))
So, even though I agree with much of your premise, there are exceptions.