My position on officiating is, "What would you say if it was the other way around?" If Martin - Manley got rocked like that on a potential game winning drive, Iowa fans would expect that call. Yes targeting is an objective call but it works against everyone. As a fan you just have to accept it and move on hoping you get the same call in a similar situation.
The opposite side is the PI call that got picked up. If that benefited ISU instead I would be saying, oops Iowa got screwed on that one. That's one that both sides can say it was a bad call.
In the end, Iowa got beat because ISU was able to finally slow down the run game and Sam was able to connect kn the passing game even without 3 of his best targets.
Iowa fans should be blaming their lack of passing game and poor pass defense. With a supposedly superior DL they got zero sacks as well.