Just to clear some things up, because I'm not sure it was clear, no articles are saying this runner was intentionally crawling "to honor his fallen comrades". He was running the race to honor is fallen comrades but his legs gave up and he fell about 50 feet from the finish.
I am a photographer and was on the photobridge at the finish line most of the race. I saw this runner and about 10 others collapsing anywhere from 10-100 feet away from the finish line. The vast majority of the runners were in the 2:45-3:30 finish time range which was early afternoon when it was about 70 degrees, sunny, and very humid. (Myself just standing on the photobridge stripped my jacket and sweater down to just my T-shirt until about 3:30 when the storm rolled in).
All other runners that collapsed welcomed the help from fellow runners or medical staff who would literally drag or outright carry the fallen runners the remaining short distance at which time the medical staff would pile them onto wheelchairs. At least 2 runners were whisked away on ambulance-style gurneys without being able to "finish" due to their condition (I assume medical staff make the decision based on mental wherewithal and consciousness).
This particular marine runner was the ONLY runner that I saw collapse who refused anyone's help. If he felt that he had to do it 100% himself in order to properly pay homage to his fellow marines, let him do that. It's up to him. To think that he somehow contrived the entire incident along with the media for his own gain is fair-fetched at best.