If you actually watch that video, Vice had to bribe a Russian border official to gain entry to the country. It's generally known as the only means of getting in with a reasonably high odds of success.

The typical experience for Americans who have applied for visas to visit North Korea is a very long wait, with only gaining approval (sometimes after years of applications), only to have the approval revoked sometimes as late as hours before their flights depart. Some people report having had their travel visas revoked three or four times before finally being granted entrance.

"Not blocked" doesn't seem like the right term for whatever that is.

I didn't recall their issues getting in, but watching it again, there were no Russians involved. They ended up going to the North Korean consulate in Shenyang, China. No other embassies would help them get in.