The reason why these countries are on the US blacklist for travel is not simply because they’re dangerous, but because there’s no real US presence in them. This means if you were to go there then there would be no US presence to call on should you find yourself in trouble. In certain countries the US is dependent on other countries to act on their behalf.
So the question becomes why would anyone need to be told not to go to certain countries? Why would there need to be an official blacklist for places you can’t visit? Well the main reason is because you have certain people who like to take risks. These people are usually journalists or other media members who want to get close to a situation for the purpose of making a name for themselves.
You might also have some US citizens that are secretly helping groups in certain countries and want to get close to them in order to prove allegiance. All of this is very dangerous. The risk is very real for serious harm or even killing. Plus, in countries such as North Korea people who don’t belong there are usually detained.
The good news about virtually every destination you’ll find on the US blacklist is that there’s no real reason why you’d want to go there anyway. There’s virtually no tourist scene and the locals tend to be hostile towards foreigners. Yes, countries such as North Korea might offer something, but it’s not worth the risk.
Instead you want to focus on destination where you can actually feel safe or reasonably safe. Destinations on the US blacklist are virtual warzones and have very rough economies. This is why things such as kidnappings and human trafficking are so high in such places.
If you’re unsure about a place you plan to visit, then you can always ask a travel agent or visit the Tavel.state.gov website for more information. In some cases even countries that are close to those on the US blacklist can’t be visited.