It has nothing to do with US citizens. Canada is extremely strict regarding DUIs and other substance-related offenses for ALL foreigners. It's their country. They can make up whatever laws they wish. If you don't like it, and you are not a Canadian citizen or LPR, then just don't attempt to enter Canada.


(Note that there are lots of countries, including many democracies with Western cultures, that have much stricter alcohol/drug laws than the USA does. Info HERE.)

IMHO, it should be zero tolerance across the board, with mandatory encarceration. The statistics are staggering of how many people are killed in alcohol-related vehicle accidents each year.