1. The average North Korean is brainwashed, or just speaks this way out of fear?
2. That Kim Jong-Un will last his lifetime as the leader of North Korea?
3. That any meaningful change will happen there during our lifetime?
4. That we will see a unified Korea, ever?
5. That the international community will do something about genocide and concentration camps that are increasingly reaching the levels of Nazi Germany?
6. Why do you think the international community is so compelled to intervene in places where the human rights abuses seem to be on a much smaller scale than what goes on here?
7. Why are high level party officials that have been part of the establishment for decades suddenly being purged? Is anything big going on, or is this just business as usual?
One of the most compelling films I saw was one about a Nepalese eye surgeon who goes over there and does 1000 cataract surgeries to help the blind see. Every single person who had their sight restored, instead of thanking the doctor, went to portraits of Kim-Il Sung and Kim Jong-Il and praised them, proceeding to state that they will work even harder now, and take up arms and wipe all enemies of the state from the planet - To raucous applause from everyone else in the room.
I'm not really used to the new bbcode formats so I've just numbered your questions.
1. With every leader who fosters a cult of personality as strong as Kim Il-Sung did there are always some people who truly do believe everything that they say. Kim Jong-Un is the continuation of that legacy. However the vast majority of citizens -- even members of the armed forces and camp guards -- are just saying paying lip service to these beliefs to avoid punishment. If you were to go to North Korea, with a camera or not, you would not be able to get the truth out of any person there due partially to suspicion of foreigners but mainly due to the fear of ending up in a concentration camp.
2. It would take a huge effort for anybody to oust him from within due to the continued purges that Jong-Un is not stopping and may even be scaling up. And the West cannot interfere due to fears of a missile attack on Seoul which is a little too close to the border for comfort, since the two countries are still in a state of de jure war.
3. Without meaning to be flippant, that very much depends on how long we live. It is possible that after Jong-Un a more progressive, western-educated and moderate leader will relax things slightly. But it is never in the interests of despots to relinquish power, and despotic regimes tend to breed more despotic regimes to take their place. A look at most of post-colonial Africa will bear this out -- so any change of regime may not bring about an increase in the quality of life of the general population. Even in Britain we didn't get things right in our first revolution and needed a second to install what would eventually morph into our current political system. So I guess my answer is that some change is inevitable, but whether or not it will be meaningful is next to impossible to say because it depends on a myriad of factors.
4. Korea will eventually be unified. It is not natural for a people of exactly the same heritage to be spread between two adjoining countries with such a disparity in living conditions. I believe that it is in the nature of the world to eventually see that (broadly speaking, and notwithstanding flukes and aberrations like slavery) all people of a certain ethnic group will have their own homeland, as has been the case in Europe since the breakup of Yugoslavia. Therefore the unification of Korea is inevitable. Whether or not it will be peaceful or soon is impossible to say -- but a regime cannot function based on extractive principles for an indefinite length of time.
5. The only thing the international community can do is sanction the Kim family and the state. There can be no talk of a military intervention -- it would place a major economic centre at reasonable risk of attack. Someone with a background in military logistics, like sivispacem, would probably be able to go into more detail here.
And it's important to note that North Korea's concentration camps aren't nearly as problematic as NAZI ones. As callous as this probably sounds, they only contain, for the most part, North Korean citizens.
6. Well, the West is not compelled to intervene anywhere -- look at the Central African Republic, or to go back in time somewhat, the actions of the Soviets during the Hungarian Uprising. A few factors that probably make an intervention in North Korea much less likely are the fact that the people are so under the thumb of Un that there is no possibility of a popular uprising à la Syria which would make it viable to secure a UN resolution necessary for military action. And then there is the threat to Seoul which has already been discussed.
There is also the issue of Russia and China. North Korea is an artificial state created in the aftermath of the Second World War after the partition of former axis territories -- just as Germany and Austria were partitioned. The principles by which the Kim family governs are/were largely Stalinist in their inspiration due to it falling under Soviet influence, while the South was under Western influence.
Then during the Korean War, while the Soviets refused to send ground troops, China did. About 180,000 Chinese troops died during the course of the war. Now I'm not saying that China and Russia are still backing North Korea because that is definitely not the case as relations have frozen a bit. This is mainly due to China and Russia believing that the Kim family are overly aggressive in their foreign policy. But Russia maintain a lot of economic presence in the DPR due to the DPR having a sizable debt to them, and China also has economic interests there. Both of these countries have a permanent seat in the security council of the UN and therefore have veto power over new resolutions. They've both voted together to prevent resolutions being passed on Syria and a failure to get them both to at least abstain would mean that any decision to act taken by the USA, the UK or anyone else would contravene international law.
Finally, there is the fact the the DPR has never gravely wronged any country other than the South militarily. Libya, on the other hand, was very much a sponsor of world terrorism and has, as a state, been behind murders on Western soil. I may be wrong but North Korea has not been involved in such incidents and therefore the isolated nature of the country makes it much easier for them to just be allowed to get on with things -- rightly or wrongly.
7. Something big may be going on, but as I've said earlier in this post the Kim family took quite a lot of its philosophy from Stalin and his domestic policies in the USSR. Both Stalin and Mao -- the two leaders who had the greatest influence on the growth of the North Korean state -- regularly engaged in purges of high-ranking members of the military and of high ranking politicians who could rival them for power (this is mirrored in the Korean purges of the late 1950's). Since his uncle was apparently the person who was in charge of the country when his father was gravely ill and was also one of the most powerful man in Korea as a vice chairman of the National Defence Commission along with a couple of other men it is possible that younger Kim was threaten by his political gravitas and as such had him purged. Likewise it is also possible that he is slowly removing all links to his father's regime in order to have his own appointees in critical positions.
Or it could be possible that there was evidence that his uncle really was trying to seize power...
And regarding the documentary, I saw the same one a year or so ago, I think on National Geographic. Unless the cameras are secret ones there is no way you can be sure that the reactions aren't scripted as Nale Dixon suggests. And even if they were secret cameras North Korean people are told from a very young age that foreigners are evil imperialists and are incredibly suspicious of us and likely to lie, especially with a gun pointed in their direction.