It is not the responsiblity of the movie industry to set the moral standard for the country. Until people demand better, they will keep getting the same crap.
They'd be better off putting such warnings on the side of that big bucket of popcorn covered with butter-like oil.
Also they could put some reminders to "wash you hands after touching that 'sticky' stuff on the floor". Or maybe show a dancing germ to explain the contaminated seats that the patrons are sitting in. "Filthy Freddy here, don't be a Mr. Yuck, wash yer hands!!!"