Are you serious? Of course it is a ruse for the tourists- Koryo Tours is not the only operator allowed to run trips there for no reason.
What you saw was just a show run by the North Korean government to further their own agenda. The people that you saw are the people that Koryo Tours (and by extension the government) wants you to see.
Make no mistake, the vast majority of North Korea is a giant interment camp. This is more like what you would see if you were to go off the shiny beaten track that Koryo tours makes you follow:
http://www.liveleak.com/view?i=1dd_1364601643
1) the Nazi's set up a "public friendly" concentration camp in the Czech Republic, Theresienstadt (1), which they took officials from the Red Cross to and used in media reports sent to the West which demonstrated the "rich Jewish cultural life." of their camps.
2) Crazy Eddie, an electronics store in the early 1980's which turned out to be a massive investor fraud, (2) had a warehouse filled with boxes so he could have an audit, a necessity to go public - the first row of boxes were filled with merchandise, the rest of the boxes were empty.
TL;DR - Humans are trusting people, show them something, and tell them "everything else is just like this thing", and most people will believe you at your word.
I'm from France, have lived in half a dozen countries and visited about 4 times that amount, currently live in Oakland and work in SF, and I'm having a hard time believing that I just read someone on HN say that living conditions for some people are worse in SF/Oakland than North Korea :)
I've recently been strangely interested in DPRK. I watched as many youtube videos as I could find and you're right nearly every tour is the same.
If North Korea interests you, I highly recommend the documentary: Camp 14: Total Control Zone. You can find it on Netflix and Youtube. In short, it's about a man born in a labor camp with no exposure to the outside world who managed to escape to China and later South Korea.
Koryo Tours is not the only operator allowed to run trips there for no reason.
Are all the other tour companies fake? They must have some seriously dedicated Western actors to spend their lives pretending they went on a tour with one of those fake companies.
What you saw was just a show run by the North Korean government to further their own agenda. The people that you saw are the people that Koryo Tours (and by extension the government) wants you to see.
Make no mistake, the vast majority of North Korea is a giant interment camp. This is more like what you would see if you were to go off the shiny beaten track that Koryo tours makes you follow: http://www.liveleak.com/view?i=1dd_1364601643