The American system was set up based on the real-life experiences of a group of humans who lived under an oppressive government. The "cultural DNA" recognizes that oppression is a natural state for authority and so what we attempt to optimize for, with varying degrees of success, is power federation.
This is not some abstract bullshit we use to justify arming ourselves. Very real suffering happens when power is consolidated with no checks, and the notion of trail-by-jury federates power in a very real way. Your opinion of the sensibility of this is not really a factor, to be honest.