Its extremism goes straight back to Flake’s hero, Senator Barry Goldwater, who saw mainstream liberals as subversive socialists and opposed the Civil Rights Act of 1964 on states’-rights grounds. In that year’s Presidential election, Goldwater received potent support from the best-selling writers Phyllis Schlafly, whose book “A Choice Not an Echo” imagined cabals of liberal Republicans plotting against the Party’s base, and John Stormer, who, in “None Dare Call It Treason,” warned that pro-Communist élites were infesting American institutions. Reagan’s famous half-hour commercial for Goldwater described the welfare state as the path to totalitarianism. Apocalyptic thinking, conspiracy theories, and bigotry haunted the movement from the start.
And this goes deep into US history and culture. cf Hackett Fischer. The violent distrust and dislike of the state was baked into Appalachian (which is a large part of the extreme republican southern culture) from its transplant from the borderlands of England.
The federalism and states rights was what kept the deeply intorelant and different initial 13 states together. The US never reached a reckoning on national culture and the accelerating centralization and homogenization of the 20th century was all but guaranteed to stir up a hornets nest.
Remember New England (itself much less violent, equitable, intelligent etc than Appalachian) flogged quaker preachers who came to Boston in the 17th centuries. They even hung them. This was an intolerant land united only in their shared obsession with liberty born of oppression back home (in England).

It can usually be found in urban city

Edmund (Ned) Searles (2010): Placing Identity: Town, Land, and Authenticity in Nunavut, Canada, Acta Vorealia, 27:2, 151-166.