It seems weirder when you say “A harmful poison that causes a slurred state and hallucinations when drunken is more socially acceptable to drink than milk”, does it? Because you can make anything sound however you want people to feel by just twisting the words around.
This! The reason milk isn’t “socially acceptable” to drink around in public is because milk isn’t really something that is commonly in a portable form factor. If you see someone drinking a milk carton in public it’s no different than seeing someone drink a juice box or a can of soda, or a can of beer. Except milk cartons aren’t really too commonly available at any gas station.