Although Jones used poisoned Flavor Aid, the drink mix was also commonly referred to as Kool-Aid. This has led to the phrase "Drinking the Kool-Aid", referring to a person or group holding an unquestioned belief, argument, or philosophy without critical examination.
Sad though, not all of those people voluntarily drank the Kool-Aid. Guess that's more reason to be wary of self-titled "visionaries". That shit that happened there must not happen again.