I saw this as a poster on a dorm wall around 1971, so It's been around for a while.
It wouldn't happen to have been in the vicinity of one or more of the following posters, would it?
"What if they had a war, and no one came?"
"We're the people your parents warned you about" (A picture depicts a mob of scraggily-looking characters, like something out of Seven Little Monsters.)
"Why?" next to the picture of a GI who had just been shot.
When I was a university student in West Germany during the early 1980s, I saw the above posters on dorm doors all over the place, often translated into clumsy German. The typically America-bashing Gerry students worshiped anything from the American left.