It's a natural phenomenon. It happens. Muslim security matters too.Your religion incorporated an abhorrent immoral act into its ethics and that's fine by you.
This is surreal to me! It's hard for me to believe that someone could be that indoctrinated.
Murder is also in of itself an immoral act (generally) but it's a necessary part of war (for the security of the nation), otherwise expect to be Shish-kebab'd.
Like murder, PoW/slavery is too generally not permitted in Islam except if it;s a result of war.