The post about combat photographers dying because of lack of fear is correct. The highest percentage of deaths among combat photographers and war reporters are those who are on their first outing and for those who have been at it for decades (Robert Capa). The beginners are unaware of certain dangers or unable to recognize them and make stupid mistakes that get them killed. The veterans are numb to it and have a "I won't get killed cuz I have been doing this for so long" mentality that they also get knocked off, usually as a result of doing something that they would have avoided earlier in their career.
Losing fear from behind the lens is natural. You're so busy with the task at hand (getting a good image) that you lose track of the scary aspects of what you're shooting. There is no doubt to that truth.
When I first started my photojournalism career I was in the newsroom of my first daily newspaper. The police scanner cracked with news of a massive tornado ripping through a small town about 10 miles southeast of us. I grabbed my cameras and drove to intersect the storm. I did about 15 minutes later as the damn thing ripped right in front of my car. It was huge and my car was shaking violently from the high winds. My windshield broke from the massive hail. But, I wasn't scared. I was shooting the twister out my window. Then, after it passed I started shooting the destruction it left behind in the small town it tore apart. It wasn't until an hour into that I found my fear. I was on a small farm shooting a family as they were surveying the damage that I looked down and saw that I was standing about 2 inches away from a live power line that had been downed. The power line had been snapped and there were sparks coming from the tip every couple of seconds. It was at that point that I learned fear, and an awareness of your surroundings go a long way between being safe and getting the good shot and just getting the good shot.