I think that's a good point and it's something I run into often. It seems like everyone expects propaganda to be so obvious and clumsy that, when it happens, they'll be able identify it immediately. But it turns out that what we're guarding our minds against is anything contrary to our existing world view, not the things we've already uncritically accepted. And what we've accepted are largely things we've observed through the lens of media.
It's also hard for people to imagine the massive scope of such a conspiracy and how it could be so well organized. It's easy to explain how media employment bias works in a hierarchy of personal interest, but that system doesn't work perfectly and it generates a lot of contradictions which I think westerners have conditioned themselves to simply ignore. Even I want to imagine the propaganda machine to be an elegant and cunning device, but the real workhorse seems to just come down to writing "China/Russia/Iran Bad" headlines enough times. Getting past that bias with americans has been the biggest challenge in my experience. It's pretty depressing.
Imperialist? You have a strange relationship with that word.