To make a wholehearted, unconditional commitment (to some group, or idea, or plan) in contrast to choosing an alternative. It emphasizes a resolute decision (good or
bad) in response to a choice.
This is a reference to the "electric
Kool-Aid acid tests," which were LSD parties held in the San Francisco Bay area in the
mid 1960's. Someone who was willing to drink the LSD-laced
Kool-Aid had, symbolically, made a choice to join (if only for a few hours) a counterculture that stood against conventional society. Once you take acid, you're committed -- the trip lasts for hours and you can't cut it
short or change your mind. Once you've
drunk the kool-aid, you're firmly committed.
IMHO it is not about suicide: kool-aid isn't a symbol for poison.
Coach got his players to drink the kool-aid.
I really like Macintosh computers; I've totally
drunk the Apple kool-aid.
That berserk
guy who tried to kill
people at the Tides Foundation really had drunk the kool-aid that the right-wing media were serving.