Man oh man. You're right for a lot of cases, but in the USA if you're uneducated, poor, and in the wrong place at the wrong time, you can get railroaded by some crooked cops and a plea deal with a crooked DA, and it's going to be small comfort that things aren't usually as bad as in North Korea
True unfortunately, but those instances are generally considered to be violations of the spirit of our system, institutions, and rights, at the least, if not also the letter, or exploitation of legal loopholes and technicalities, depending on jurisdiction. And we can publicly raise hell about it, protest, lobby, and elect reps who will work to fix it and close the loopholes.
In authoritarian systems, those instances are in accordance with their system. And while people there do sometimes raise hell about it, sometimes they're ignored, sometimes they're placated, and sometimes they're disappeared, depending on the whim, temperament, and calculations of whoever is in power, with zero recourse.
Nobody is arguing that the system is perfect. Yes we know bad things happen and there are bad people in the system who prey on others. That's true everywhere and it should go without saying.
It doesn't change the fact that the US is very different from NK and not really at all comparable if we are being intellectually honest.