I know the US isn't perfect, but is it the kind of repressive regime that the Tor project talks about? Or, to put it another way, should Tor consider it a success that they can take down regimes no more repressive than the US?
I won't be drawn into a debate on relative repressiveness. But consider how LGBT activists were generally harassed a decade or two ago. And still are, in some parts of the US. Or the War on Drugs.
I'm sure that some Tor supporters in the CIA are hot on taking down particular regimes. But I don't recall seeing that as an official Tor Project use case.
Regarding the example of North Korea, I'm sure that there are ways of hitting Tor. At least, if you can reach the Internet at all. Maybe it's not worth the risk, however.
Maybe they stopped making a big deal about it, but it was one of their "we make the world a better place" use cases when they started out (of course, they also said "no warranties that we got the security perfectly right").