Don't let it bother you, we would probably be whining too if Petras would have gone out early 4th quarter.
Regarding the fake-injury stuff, there was really just one obvious one (DE17 after a nice Goodson run). But he just happened to dive on the turf in front of God and the entire Kinnick stadium crowd. There was no booing before that one, but after that obvious fake-job, everyone started booing every injury (the rest were probably legit). I can't fault PSU for being a bit upset about that, but I can't fault fans for booing when one guy clearly takes a dive in front of the whole stadium.
I can even go Devil's advocate a bit further...as a defender, if you are even a bit dinged and need to come out, you absolutely should hit the turf. At least give the coaches an opportunity to make the right sub and get everything in order. No need to stay there for 2 minutes will the trainer fake-checks your knee, though.
Just my opinion but after the first (even if it's the only) fake injury I don't think it's fair to say the rest were probably legit, because the burden of proof is no longer there. So unfortunately they brought it upon themselves.
And I agree with your devil's advocate approach, but at the same time if it were legit you'd see it occurring as frequently during plays that resulted in an Iowa loss or no gain. I didn't rewatch the game, but if I recall correctly I didn't think continually moving the chains meant stopping the game for another injured (and I use that term loosely) PSU defender. I'm with you that in trying to look at it from another angle to preserve the integrity of opponent, but in this case, as with MSU, there's a different set of rules being used.