Im seeing the "smart" pro-Trump crowd acting as if he played North Korea and there is some grand strategy behind this. Their reasoning is that he got them to destroy their nuclear site, then pulled out without any concessions.
Here is a premier arms control expert on how the site destruction is likely reversible:
Analysis by Mark Fitzpatrick, executive director, International Institute for Strategic Studies-Americas
Destruction of the nuclear testing tunnels at Punggye-ri is a demonstrable, tangible step toward the denuclearisation goal that leader Kim Jong-un agreed to at the 27 April Panmunjom Summit.
However, North Korea should have allowed experts from the Comprehensive Test Ban Treaty Organization to observe the tunnel collapse. Not doing so signalled disinterest in verification standards that will be required for any denuclearisation agreement with the US.
This harks back to the situation in mid-2008, when, with cameras rolling, North Korea destroyed the cooling tower of its plutonium-production reactor in Yongbyon, but a few months later refused to accept verification requirements to prove that its declaration of plutonium production was complete and correct.
Negotiations collapsed and North Korea went on to re-use the reactor after installing a different cooling system.
Similarly, North Korea could easily construct new tunnels to resume nuclear testing. Still, the collapse of three existing tunnels, two of which appeared to still be operable, is a welcome first move. It will undoubtedly want something in exchange before it takes more steps.
Taking this into account, along with the Koreans surprise, and its clear this is an extremely impulsive move. I do have to say, Trump has a more effective propagandist in Pompeo who can more effectively communicate his random actions and make them seem logical.