Sean, you'll get no debate from me. Can only speculate on the reasons why the review went as it did and consider the reasons why. Suggesting such doesn't mean one agrees with them. Just recognizes what they might be.
I am glad such a review wasn't mine to do. I have a hard time not bowing before heroes and would award too easily I fear. Knowing only the public facts I can't fathom the decision in this case. But such decisions are well well above my pay grade.
The First Sergeant (now Sgt Major) who shielded a wounded Marine with his body (made the news getting carried out by two Marines with his M9 still in his hand) from an insurgent grenade during the battle of Fallujah "only" got the Navy Cross. Some believed he rated the Medal of Honor as well...guess that is the bar in some way. Dunham wrestled an insurgent and then jumped on a grenade knocked from his hand, put his helmet over it and took the blast...not much different then Peralta.
I hope there is not some stupid quota in place...but on the whole, my Corps is much more stringent then the other services about issuing any awards, valorous or not. (and I have done joint tours, so have seen it from different aspects).
Sean