On the other hand, why even torture someone and then let them free so they can speak out against you? Torturing seems like such a hassle.
If I were an evil dictator with the means in the modern day and I wanted to really intimidate a population, I would abduct some of that population and just secretly kill them and burn their bodies. Nobody can then prove whether you actually killed them. You could say you re-educated them and then let them go, and their present whereabouts are no longer your business.
Also it's pretty clear that they don't care about eliminating the people - they want to eliminate the culture.