Because Irish
I used to do such things, like 10 shots in a single glass for fun. The highest I went was 151 which was simply called 151. Now there are apparently a lot of 75.5% alcohol varieties I didn't know about.
It was awful ofc. My fav was Grey Goose Vodka straight. But only the top 80% of the bottle, the bottom was so bitter as to be undrinkable.