you seem misinformed, ‘carnist’ and by extension ‘carnie’ has nothing to do with the carnivore diet, but with carnism:

Carnism is a concept used in discussions of humanity’s relation to other animals, defined as a prevailing ideology in which people support the use and consumption of animal products, especially meat.[1] Carnism is presented as a dominant belief system supported by a variety of defense mechanisms and mostly unchallenged assumptions.[1][2][3][4]