It is still part of the country of Canada. My point was saying Canada uses bags of milk is no different than saying Americans do X when its only Florida or a handful of states.
Today, Ontario, Quebec, New Brunswick, Prince Edward Island, and Nova Scotia all have bagged milk. Between them is 26 million of the 40 million Canadians, so the majority, 65%, of Canadians have access to bagged milk.
It would be more accurate to portray Western Canada as "only Florida or a handful of states".
It's just a stupid meme from the old internet, circa 2004: https://knowyourmeme.com/memes/in-canada-milk-comes-in-bags