Some parts of Canada dispense milk in bags. It comes in a plastic bladder that you pop inside this pitcher and cut the corner off to pour. This shitpost is pretending that we pour the milk into the pitcher directly and store it uncovered.
American here. I can't speak for all Americans, but I think it's weird that you leave it in the bag, in the pitcher. Why not just pour it out of the bag, into a pitcher that has its own lid?
Because then you'd have to wash out the pitcher each time, keeping it in the bag means you just toss it and replace with a new one. Also I think the pitcher milk would spoil faster but I'm not sure about that