When I first moved to LA in 1987, I couldn't believe the litter I saw everywhere. I couldn't grasp how people could just leave trash everywhere.
And it's not a demographic thing... I saw it at LSU after football games, wherein even the wealthy tailgaters left their shite everywhere for someone else to clean up.
Instead of "Give a Hoot, Don't pollute" it is "Don't give a shit, let it sit".
Up here it's not near as bad despite this being a relatively poor area of the US (but not nearly as diverse as LA).
I guess some people just respect the environment more than others.
Conservation is conservative, an idea that seems lost on many otherwise conservative folks in LA IMO.
Maybe it's because the social trust levels in LA are so low?
More research into social or societal trust levels in relation to the diversity of a population might be in order to gain a better understanding?
Here's a good start for those so inclined: LINK
Google this: diversity versus social trust levels