Well if you'll indulge me, I will answer your question with rock 'n roll:
All good soldiers fall in line
when they march and shout
are a spectacle
marching and singing
they'll go anywhere the president says
because the president believes in god
like all good soldiers should
- Bad Religion
I cannot see how these soldiers reaction should have overcome your skepticism. All you saw was evidence of BELIEF - not evidence of TRUTH. I am sure there are countless examples of Muslims who have suffered, and then called out praises to god upon release. Is that evidence that their belief is true, or just evidence that they have belief?
It is very useful to have religious soldiers. After all, they are promised an afterlife, so what do they have to lose? And thats just what you want in a soldier - bullet catchers for the slave masters.