Calpis isn’t carbonated tho, at least none of the Calpico branded stuff I’ve had. Milkis is very similar and is carbonated, so it would probably be closer to this. Personally I like both Calpico and Milkis, they are definitely not my favorite but they are good to have every once in a while, owing especially to their unique taste.
https://en.m.wikipedia.org/wiki/Argument_from_fallacy
Besides, that isn’t even an appeal to tradition, because they aren’t arguing that something is correct because it is traditional, but rather specifying that the tradition is de facto practiced and accepted.