“Because we are free men, we will be free to measure liquids in liters and milliliters… but not all liquids, only soda, wine, and alcohol because for milk and paint we will use gallons, pints, and quarts, god willing”

“How many liters are in a gallon, sir?” “Nobody knows.”

“Why not use meters and kilometers?” “We sill, soldier. But only in certain unpopular sports like track and swimming.”

If we assume Bigfoot exists and is intelligent, I would suggest they are more like an indigenous tribe or people like those un-contacted tribes in the Amazon rain forest or the folks on North Sentinel island.

Kind of left alone to manage and govern themselves.