Few people can comprehend the amount of brainwashing in North Korea. If you want to start to understand why they likely will not rise up against their government, watch this. Then watch the full documentary. It is amazing.
Fast forward to about 2:30 to witness the brainwashing.
That doctor was allowed into North Korea so cataract surgery could be performed, and he could train North Korean doctors on how to do it. He got no credit from his patients.