Seriously? We should never kill enemies in time of war?I agree, it is wrong no matter what.
We should, but we should not define battlefield in a way that allows us to kill people who are not actively fighting.
The propaganda minister of Nazi Germany was actively fighting.
I decline to let you unilaterally define the meaning of "fighting" to exclude a guy who enlists the enemy recruits and exhorts them, successfully, to kill our people. Such an enemy leader in many ways is a much more urgent and important a target than any one combatant in the field or any set of hijackers on passenger planes.