drunk the Kool-Aid

Verb

drink the Kool-Aid (third-person singular simple present drinks the Kool-Aid, present participle drinking the Kool-Aid, simple past drank the Kool-Aid, past participle drunk the Kool-Aid)

1. (US, colloquial) To come under the influence of a leader, organization, or movement to the point of believing uncritically in an espoused idea or ideology.
   • Outside the Convention Center, meanwhile, protesters on either side of police barricades waved signs, chanted, sang songs and heckled people walking inside to attend the fundraiser. Signs included "Limp Wrists Make Strong Fists," "I'd Rather Be Dead Than Born Again" and "Abort the Moral Majority."...1982 April 24, Claude Peck, “Demo Greets Falwell During Visit to Minneapolis”, in Gay Community News, page 3