Because religious conservatism has pretty much always been focused on supporting systems of authority, and in the US the system of authority is capitalism.
People would probably be really surprised to see what ‘heretical’ sects of Christianity were talking about in the first few centuries compared to the version that was green lit by the Roman empire on the notion that political power was divinely intended.
Straight up comments attributed to Jesus decrying dynastic rule (seemingly referred to by Paul in 1 Cor 4), a parable about assassinating a powerful person, discouraging giving any money or rewards to prophets or priests, rejection of prayer and fasting and alms as either useful or necessary, and even discussions around Greek atomism and Lucretius’s version of survival of the fittest.
And that’s all in only one work/tradition.
But it’s one that was buried in a jar for millennia after canonical Christianity was endorsed by the emperor, which followed with deciding what texts to allow and what to ban on eventual penalty of death.
The thing most people in the US believe today is the version that passed the filter of the Roman empire’s oversight and involvement, from killing the initial leader to endorsing the eventual version that’s probably at odds with the original teachings in places.
It shouldn’t be a surprise that it goes hand in hand with boot licking and anti-critical thinking.