Indiana gets little to no credit because (my opinion) college football fans and commentators are largely a bunch of lazy morons who don't understand that football is played on defense just as much as on offense. They like to watch the pretty football go all over the field. And they never learn anything about defense and schemes and percentages of stops and stealing points (ex. three vs seven) etc etc etc. They are marginal at best offensively-knowledgeable and right up to zero or minus defensively-knowledgeable. Plus the average fan seems to look at single players in a given play and think that tells them what all went on. Amazes me. It is a rare fan who has a coach's eye and holistic game awareness.
Ask Al Golden whether our defense is just as important as our offense in winning games --- then ask Mike Denbrock the same question and get the exact same answer. Both those guys knew how good Indiana's defense was, and (when the season is over) I'll bet they'd say that it was better than Ole Miss's D or Bama's D, or a lot of other criers.