Because IF we're really gonna entertain playoff talk, then when it comes to the CFP committee, they are a bunch of lying as* hypocrites and absolutely LOVE them some transitive property, especially when it comes to splitting hairs about who should get in and who shouldn't.
Michigan has a home win over Oklahoma who just beat #1 Texas. Iowa has a road win over that same Michigan team.
Obviously things will look much different by November, and they already do now given that we broke Michigan and Oklahoma woke up long enough to win their Super Bowl, but in the mean time, this only helps Iowa.