states run themselves, and the federal judiciary basically only steps in when state/local governments don't follow their own rules (the presumed expression of the will of the people) or violate the constitution. the constrained executive response follows from the judiciary (and sometimes the legislature).
and that's the way it should be. you want power local and limited, not consolidated and far away. that would only make things like use of force worse.
so the immediate appeal to authority should be to the local, and then state, judiciary and legislature stepping in with corrective actions. the feds aren't of much use here. they're intentionally a line of last (and slow) resort.
Maybe in your country but in many, many places in the world this is demonstrably not the case.
as with markets, idiosyncratic conditions like sociopathy can lead to pockets of undue concentrations of power, no doubt.
but it would be even worse if those same conditions were concentrated on and elevated to wider populations. by distributing power, you can more effectively pit one against the other, and have some chance of bettering conditions over time. those chances decrease with power concentration.
it's worse if we had the same sordid problems at a state or national level. it's rolling the dice once or 50 times vs. rolling them ~50,000 times.