You are taking a very strange approach to classifying top 25 wins. The overwhelming majority of people talk about ranked games when they are played, not based on final rankings. Using AP rankings at time of game played, Texas was 6-3 and IU was 0-2. Trying to discredit the Texas schedule as similar to IU the way you have is very odd.
The fact remains that IU had an extremely soft schedule, and they took full advantage of it. IU and Rutgers were the only B1G schools to have only one ranked opportunity through the regular season. As I stated, it is simply rare to be in a power conference like the B1G and get to 11 wins without a ranked win. For context, Illinois got to 9 regular season wins with 3 ranked wins. That is why I am so proud of what the Illini put together last season, and I am very confident Illini would have beaten IU last season. The good news is that the Illini have the opportunity to do that this season, and the way IU has scheduled cupcakes again, I think the Illini will be much more prepared than IU, given the Illini will already have a road game against Duke under their belts.