Thank you, Kate for defending peple having a higher ethical standard in the little and big things and how they interrelate for our planet's health. I didn't know there was this litter problem on such a scale.
"Are we going to keep messing things up and wait around for Mommy Earth Maid to clean it up for us?" I once saw an nspiring example - after a big fair a woman I knew went around the whole fair picking up trash on her own initiative. The incident you mentioned sounds like a very ucomfortable interaction - you were being courteous and you got that disrespectful response. People really affect others around them even though they might pretend or ignore that they do.