I think you are a bit off here. Kerry exaggerated the injuries to get to go home early. His three purple hearts were his ticket home.
Your version might be closer to the truth, but my version will play better towards undecided voters. Faking the severity of the injuries for medals is harder to swallow than faking injuries to go home earlier.
I don't believe that was his objective. I think he was going for medals.
It was one of his commanding officers that told him to leave after his 3rd purple heart because he thought he was unfit for duty.
The other reason I believe that is because of what Kerry said to one of his men in Nam. He said, "I will be the next JFK." In other words he is emulating Kennedy, which in my opinion is why he joined in the first place.