not totally insane but if he thinks President Trump is going to sit on his testicles like the other three presidents you mentioned, he is nuts...
This could be messy but it’s like gangrene, you have to deal with it at some point.
North Korea has been mostly just talk for many years, but they have had a few episodes where they actually did harm across the border, and they seem to be quite active in the hacking area, with what effect we don’t really know (I assume that the NSA does know, but we can assume it’s like a 3 on the 10 point scale where Russian hackers might be more like a 6).
If I were Trump, I would send them a message through a third party, hey a-holes, one false move and you’re done. Then surround them so they get the message.