John Birch Society
The organization was started in association with the revelations of "McCarthyism" on widespread Communist infiltration in the United States. The John Birch Society took this further, sometimes stating extreme conspiracy theories regarding the extent of Communist influence.
The organization initially opposed the Civil Rights Movement, possibly due to correctly suspecting Communist influences. Regardless, the organization accepted non-Whites as members and even the leftist Wikipedia does not accuse it of any form of "racism".
The leftist Wikipedia does, however, cite dubious (leftist) claims such as "Bircherism" and its legacy of conspiracy theories has become the dominant strain in the conservative movement", "a resurgence in the mid-2010", "many political analysts from across the spectrum have argued that it shaped the modern conservative movement", and "the intellectual seed bank of the right", possibly as attempted guilt by association.