Really? Like I said earlier, I grew up in West Lafayette literally 5 min from the Purdue campus. My high school was filled with professors kids and was across the street from Ross Ade Stadium. My mom still lives in town although she moved a little farther away and is now neighbors with Matt Painter (~15 min from campus). I remember going to most home games from when I was in 3rd grade until I left for college. My love for Purdue has been for pretty much all my life while there are many alumni that started being fans at the age of 18. I chose to take a better opportunity in the northeast for college, but Purdue bball and football are my first loves in sports and that will never change despite the decades of heartbreak. Maybe there should be an exception for “townies” that chose to go elsewhere for whatever reason.
Like I said, it doesn't make anyone less of a fan, in fact you may very well be a more hardcore fan, but it's a different relationship for those who went to the school. For those who went to the school, it's not just a team to root for. I'm not surprised at all you classmates who went to IU root for IU over Purdue. I would be shocked if they didn't.