Consider one example of how propaganda works in the American education system itself. Take your grade and/or high school history books. Have you ever wondered who wrote that chapter on "The Civil War" or "The American Revolution" that appears in your monolithic 8th grade history textbook? Who produces those textbooks, who writes them, who profits from them and how are the historical narratives determined? There are rarely if ever any clearly defined authors in such books- it's as if god has sent down scripture to our local school and we as "good citizens" are to accept these holy words in these sacred texts as absolute truths.
There are a plethora of different sources, and financial beneficiaries, for texts written about our historical wars. I can't take your stance seriously after you tried to make the case that it's difficult to weave through the propaganda on these topics.