Bolton mentioned the "Libya model" might be how NK goes, North Korea got upset about it. Why would they get upset about it to the point of talking about cancelling this summit is telling in itself.
Saying things such as Libya was peaceful afterwards in 2009 or whenever it was, seems to have a limited bearing to the direct reason, NK got upset at all. It almost appears ludicrous to discuss this.
I'm going to drop this part of the conversation; there are plenty of articles about this. One can't even be certain what is the point of debate from the opposite end.