Sometimes used by aficionados of the 1911 handgun ("Colt .45") to describe fans of the Glock (or other polymer framed) handguns - possibly a reference to the nickname "tupperware gun" and the typical serving of Kool-Aid in plastic pitchers.
In more recent use it may also be applied to folks who think that any negative term or euphemism applied to President Obama or his acolytes automatically means the user is a racist.
The suggestion that the term applies only to a stereotype of African-Americans implies that no Caucasians drink Kook-Aid, an obvious fallacy and an indication of a significant pre-existing bias on the part of the writer, or a blatant attempt to suppress freedom of speech on the part of opponents.
From the followers of Jim Jones in Guyana who committed suicide by drinking poisoned Kool Aid.
A Glock? What are you, a Kool Aid drinker?
The term is in reference to the religious cult led by Jim Jones, who committed mass suicide by drinking Kool-Aid laced with Valium and cyanide.
a koolaid drinker is the liberal democrat who is liberal because they are told they should be. they have made no attempt to decide why the are liberal.
often a koolaid "drinker" simply wants to hate anything a republican does good or bad.
koolaid people are the vocal howard dean wing of the democrat party. the converse of rightwing loonies.
koolaid drinkers are the ones that went first when jim jones said drink.