To the original poster, why if all these plastic things are OK and plastic grocery bags not? It's simple. You don't generally see ketchup bottles hanging in the trees close to landfills that the wind got a hold of and blew away. The wind also cannot get a hold of the used Greek Salad container either and blow them into a waterway. Ever take a drive West of London past the giant landfill close enough to the 401 to smell? Check out the trees surrounding it. "garbage bag trees" is a great line in a Tragically Hip song.
Plus, what plastic can we get rid of easily enough? Ketchup bottles? Not easy. Food containers? Not easy. A plastic grocery bag is actually an easy one to eliminate, convert it to paper...which we have lots of papermills in Canada and a lot of trees. Plastic straws to paper? Great idea, the mill in Espanola Ontario is going to make them where a few mills in BC already are.
Moving away from easily replaceable products like chinese-made plastic bags to Canadian-made paper bags is a great idea.
A poster talked about grandparents...they bagged their groceries in paper bags! I am old enough to remember that. Watch Shawshank Redemption...those are paper bags 'ol Brooks was bagging.
Plastic will never be replaced, too many products need it, but everyone has to at least admit we need to do better. All the news of plastics in our waterways is a major problem, cannot deny it. Must eliminate where we can easy enough, plastic grocery bags is a prefect example.