That has nothing to do with safety.
One can be as hypocritical as one wants about places like North Korea, Myanmar, half of African nations, Middle Easts, stans, and many others. Ignoring them? Right, they'll change to good by themselves. War against them? Right, that has worked pretty well, too.
With North Korea a reason to visit can be pretty simple -- to learn and to show. If they have been told that westerners are imperialists that only want bad to them, what is better than showing them a person that is interested in their culture, polite, non-aggressive, and friendly -- especially with the children. Perhaps it will help to seed a change.
One can bring magazines and newspapers to North Korea. If you read the Guardian and then Pyongyang Times and the latter tells a different story, you believe the Guardian -- of course. But if a north korean reads them, he will believe Pyongyang Times. Even you can't be 100% sure the Guardian is right, it's all about what you believe. Say Fox News had a story.. ok, let's not go there
Just to say that we're inside propaganda as well, living in a bubble.
One guy said, "the more I travel, the less I understand". Well said.