Well, don't get me wrong... the propoganda style could be effective if you take it to a ridiculous extreme - then it's clever.
Also my point was not that today's youth are knowledgeable and will react negatively to propoganda. It's that we've grown up on television, action flics, bright color magazines, flashing billboards, the 30 second advertisement and the 5 second sound byte. Our eyes simply move right over things that don't reach out and GRAB them.
In more ways than one, we're very close to the futurist style that grew up with the fascist states in europe - speed, progress, conflict. The difference is that the media technology they had available was much more subdued and limited.
So, a propoganda poster that's flashy and over-the-top in its message could work quite well.