I don't dispute the US is non ideal, I do dispute that as a whole the government is unaccountable. For example, what do you think would happen if Gavin Newsome (governor of California) had someone killed for disrespecting him? That's the kind of thing really unaccountable governments get away with.
So I'm asking you to not only show that bad things have happened and not been adequately punished, but that the government is fundamentally as unaccountable as a reference unaccountable government, like the U.S.S.R under Stalin or Britain under Oliver Cromwell.
Yes, that's an extreme requirement. But you made an extreme claim when you said not just that democracies are insufficiently accountable to be completely just but that they are unaccountable.
Of course many governmental officials would likely be held accountable for extreme misconduct if they weren’t able to cover up the evidence. And of course certain governments are more accountable than others.
And I'm asking you not just to show that a bunch of bad stuff has happened, but that in its totality at least one country most people would consider a democracy (a good but imperfect shortcut for this is if Freedom House rates them as such) has essentially no accountability.