Places that still have open defecation and garbage in the streets have bigger issues to be solved before we deduce plastic bags are the problem. E.g. third world.
Seattle and SF have banned plastic bags and the streets are still littered with human feces. Maybe for their next initiative they should pass out reusable bags for people to poop into. Sorry but a feel good measure to make grocery bags illegal doesn't move the needle for me when I still have to play hopscotch with literal logs of human shit.
