Stupidest thing I have ever heard.
I believe it depends on the circumstances. Like in WWII we would do bombing rungs and shoot into bomb factories. These people were "civilians" that were working with the enemy (referring to the Allied Powers against Axis). These shootings and bombing killed the people working there, but it stopped the production of weapons and munitions that were going to be used against our own forces.
The term "civilian" is overused in modern society. If your nation occupies an area and the occupants want you out, they are not civilians, they are combatants imo.
EDIT:
Can you name a time that a nation who occupied another nation has NOT used propaganda? The US is a super power because there are many willing to fight for the freedoms they receive in the USA. Do I think the government lies to its people? To an extent, yes, BUT to be clear, I think there is sometimes a need to lie to citizens. We don't want to cause mass panic because the president's briefing included a potential terrorist attack, although the odds of it happening are extremely low.
America. Love it, or leave it.