I agree that the flight deck is extremely dangerous. In his book the Right Stuff, (although he was referring specifically to the aviators, enlisted personel are at risk too on deck) Tom Wolfe cites statistic that those in Naval Aviation had a 20% chance of dying... outside of combat! as late as the 1970's.
But one thing though is... as long as everyone does their job right and proper precautions are taken.. i'd think that most of the dangers can be minimzed. How many fatalities have their been on the flight deck in the past 2 years (compared with Marine causualties on the ground)? I will concede though that the lack of fatalities on the flight deck is more of a tribute to the skills of those who do their jobs correctly and make it look "easy" as opposed to the dangers being any less.
But where i do defer is on the following point: How many on the flight deck are being targetted by the enemy and shot at while doing their jobs?
I think this is what makes being an infantry Marine (or seabees, etc..) more dangerous.... actively having the enemy targetting them in their gunsights.