"...they are not there to change anyone's religion."

That depends how you define religion. I suspect that worship of "the free market" is probably the fundamental religion within the seats of power in our societies, rather than a Christianity which profoundly challenges the validity of such worship as a foundation for a humane society.

Incidentally, and apropos of nothing, it's very strange
to have troops stuck in the middle of a desert, hundreds of miles from the sea, and called "marines"...