I dunno. People can DRINK 1 liter of vodka pretty quickly and not die, but the alcohol starts to get metabolized pretty quickly. Having 40cl of ethanol (1liter * 40%) in you some time after consumption...

cargoship should have been under the exemption for the people > 21...

However it appears that > 21 year olds were also denied entry. That seems very wrong. However, public intoxication is a crime in most the US, so the border guard was preventing the commision of a crime.