Politics be damned. Give them something reliable.
Wars are fought with rifles, not politcal correctness.
Sorry, the world doesn't work that way.
"War is the continuation of politics by other means."
--Karl von Clausewitz
And yes, I've put my gun through the same kind of environments as the military does. I'm not a benchrest shooter.
Why haven't I had any problems? I take care of my gear. My rifle is kept in good repair and I clean it after shooting.
I've engaged targets out to 600 yards with my rifle (M4 configuration) with no problems. The M4 is a fine rifle and very reliable. It's a good decision on the part of the Marines to move to it.