"War is not healthy for children and other living things."

It's hypocritical to expect any armed force to behave in any manner
that doesn't reflect the entire spectrum of personalities comprising
the force itself.

An unbalanced, homocidal, whack job who finds his or her way into the
armed forces (and the vast majority of servicepeople cannot be so
described) then becomes an unbalanced, homocidal, whack job with a gun,
or a bomb, or a tank, or prison guard's uniform.

The jerks killing off prisoners do not represent the military in
general any more than the super-heroes who earn the Medal of Honor,
etc. Most everybody is going to be somewhere between the two extremes,
just like in "real life".