This allusion to fervent loyalty harks back to the 1978 Jonestown, Guyana massacre in which hundreds of followers of the Rev. Jim Jones obeyed his orders to commit suicide by drinking a cyanide-laced fruit drink (Flavor-Aid, actually, not Kool Aid). Ever since those who blindly follow another person or ideology are said to “drink the Kool Aid.” They are “Kool Aid drinkers.”
