Since when? If they are, then I guess they forgot to tell all the stores in SoCal that. Only thing that has changed is they charge you for every plastic bag that you use - 10-15 cents each. Plastic straws, OTOH, are banned outright.
Maybe this is a county or city issue? Last store I was in was Grocery Outlet in Truckee, California.
I don’t think you get charged for the thin plastic bags, just the heavy duty ones. And I’m drinking an ice tea from Panda Express right now with a plastic straw