Play video content EXCLUSIVE TMZ.com

Sacha Baron Cohen is unfairly making the citizens of Kingman, Arizona look like a bunch of backwater racists ... according to the city's mayor.

Mayor Monica Gates tells us last week's episode of "Who Is America?" is total BS because she doesn't think it was even shot in her city. She says she doesn't recognize the venue or any of the people in the room.

The segment was supremely unflattering to Kingman -- a disguised Sacha told the roomful of citizens the world's largest mosque outside of the Middle East was going to be built there. The reaction ranged from hilarious to scarily racist ... not only against Muslims.

As for the people in the room NOT being legit Kingman residents? Some of the people who got duped sounded off afterward, and we checked the names that were public -- they DO live there.