There is a spectrum of this kind of thing, pure outright lying and stolen valor on one end, and first-person stress narrative on the other, with everything else falling in the middle. I get the first-person stress narrative, I see this every day: "I fell 20 feet." No, it was 5 feet. "The car was going 60 mph." No, the car was going 20 mph. They aren't lying, the stress of the trauma just changes your narrative. I give vets who were in combat a little leeway because of this. Shit, I misremember things all the time.
This is different from the overt lying, whether it's Luttrell (or others) refusing to acknowledge that he's been caught per
@AWP comment or the quasi-stolen valor Marine per
@Teufel comment. That may be a whole other thread, deep diving into why people feel compelled to have to do this. I go from mad to sad to mad with these folks.