Tens of thousands of people who had a clear motivation to come across as upstanding citizens, and who generally had a political leaning towards environmentalism. I can believe they didn't leave trash behind.

See, that's the kind of thing that can happen when you value community and work together. You can have significant and nice shared resources. It's not a tragedy of the commons race to the bottom you get with rugged individualists and/or selfish children who see trash on the ground and say "that's bad, the person who did that needs to clean it up and be punished" and then it sits there and rots.

And yeah there are WAY more important things to worry about than how various groups do or do not litter. But it is an illustrative example of the different priorities and values of the groups. It seems like a topic for discussion as we live in a world where some people are still somehow just finding out that this Trump character might not a be all above board.

But for something so minor why are you so insistent upon pushing it away and disregarding it? That's two different justifications now for doing so (these are cherry picked, ok maybe not but it doesn't matter).