They don't taste good but they're cheap and strong so they were popular with college kids looking to hang out and get buzzed with friends. Even then we sort of did it with a wink and a grin, knowing that we were drinking some pretty "trashy" stuff.
"Buckfast gets you fucked fast!" was the common joke.
I recall people hoarding “original formula” watermelon fourloko when it started disappearing from shelves.
Edit: a decent overview of the “banned” four loko vs reformulates version: https://youtu.be/XUPXFzag258
Fourloko seems to have a similar reputations with my friends from universities across the pond, but is a fair bit less alcoholic, and served in large beer can quantities rather than 750ml wine bottles. If you down a bottle of Bucky you’re having a night you probably won’t remember.