I don’t believe for a second that the Norks are developing this missile threat on their own. I would say the Red Chinese can send them complete ICBMs by plane anytime with techs and support equipment correctly designed to look like it is Nork made.
And lets not forget that before the Russians put those missiles in Cuba there was the Bay of Pigs in April.
The Sam sites that were to protect the SSMs were discovered in August. That I believe is what led to the missiles going to Cuba.
The Norks are getting help, but they are not getting complete ready to launch systems from China, so it’s not as blatant a case as Cuba.
Bottom line is we have to deal with each threat appropriately for the circumstances at the time. China isn’t going to go nuclear over us taking out NK. They will draw their own redline over what happens after the regime is gone.