Thise countries or any other country are the result of the actual global system. Few siecles, feodalism and slavery the glbal economic system so it's barely impossible not to find slaves in any part of tge modern world at the time. By time goes by, with the current glbalization era, it is a must for any country to follow the system because there is no way to isolate itself. See the example of North Corea which can't apply such a dictatorship without disconnecting from the whole world.