I think they way mezcal was marketed to US tourists (and back home) in the 60s and 70s was to confuse tequila with mezcal. I have older friends who have complained about horrible hangovers and generally being sick after drinking tequila in their teens and 20s, but whenever I question them just a little bit it turns out they had mezcal (and cheap mezcal, like Gusano Rojo), not tequila.