Also, you mention missiles at their best are used as a deterrent. That might keep one nation safe, but is is still about spreading terror to others and tends to

Also, you mention missiles at their best are used as a deterrent. That might keep one nation safe, but is is still about spreading terror to others and tends to just fuel arms races. Ads at their best (aka, furthest removed from propaganda) are about informing people of things they would otherwise not know about. Think, mom and pop sops, some new organization, or a science fair. It's easy to paint things black and white, and there's a line that can be crossed in terms of tracking, optimization, and attempts to control the population/public opinion. IMHO though, I really do think engineers working on companies in the ad space are not as ethically removed as those working on machines meant to kill.