Back during the first season of Mad Men (set in 1960), I was amused by a scene where the family had a picnic in a public park, then dumped their garbage on the ground and drive off. At the time I assumed it was a somewhat exaggerated scene meant to add some period flavor, and didn't think much of it.
More recently, I was having a conversation with a friend who works at a nursing home. The staff had recently taken part in an "adopt a city park" program, and had taken a group of senior citizens with them to walk around a park and pick up litter. She mentioned that while all the staff were enthusiastic about the trip, a large number of the older folks were completely mystified as to why they should bother picking up litter, like it was a foreign concept.
Was public opinion about litter really that different in the post-WW2 era?
Was there any vocal dissenting opinion or public debate about litter at the time?
When, how, and why did things change? I assume any shift would be connected to the environmentalism movement of the 1970s, but what was that transition like?
How did we get from the Mad Men picnic in 1960 to the crying Italian guy in "redface" in 1971?
Here is a link to an earlier thread that does a good job of answering this question. That thread was also inspired by the exact same Mad Men scene and the top answer briefly touches on the 'crying Italian guy in redface', so it should be the exact kind of information you're looking for.