Same thing happened in Vietnam. In fact, public opinion only really changed after the politicians started saying that it was ‘time to scale down US involvement’ or whatever, which only came years after many people in the Whitehouse realised the war was unwinnable. In the meantime, and despite all the famous protests and anti-war marches, the public was pretty happy to follow the official line that America was the good guy and that communism had to be stopped.
You could do an interesting analysis of this phenomenon using Gramsci’s idea of Cultural Hegemony as a framing device.
I find the original trollface works well. Just the right level of rage-inducing “tee-hee” ironic detatchment that makes a poster a poster.