Some people are brainwashed into thinking that we are saints. As you can see in this thread, however, there are a fair amount of people that are quite aware of the United States' issues.
(I also think it's not that great to cartoonishly portray Nazi Germany / ISIS / Saddam as one dimensional stock evil cartoon characters; this is also a sort of "brainwashing" from my perspective. Yes, these cultures also have done some awful, awful things, however I feel it is important not to erase the human impulse and circumstances that caused these to develop.)
From a general audience perspective, I'm personally pretty cynical on addressing this though. In theory, it would be nice to see an end to "mass propaganda and willful ignorance". In practice, I honestly can't think of a country in which no propaganda occurs, and there is no such thing as state secrets. The United States may have done some awful things over the last 70 years, but so have other less powerful countries. Were the situation different, and another country dominant instead of the US... well, I personally would expect very similar results. I can't think of any nation / community / tribe that doesn't do some sort of bending and filtering of worldview.
So from my perspective this really isn't a nation problem, this is a core human issue: tribalism. Resolving the issues that come up with tribalism would be great. However, given that it's such a core behavior of humanity, I think this is going to be terribly difficult, perhaps impossible, to do.
It would be nice if I was wrong...