The Republicans don't believe in conciliation, in solving conflicts or even avoiding them! They believe in conflict! North Korea is MUCH more useful to them as an enemy, a threat to our way of life. Iran too. Even little Cuba!
That's part of it. The other part is that Trump sees himself as a master negotiator. Basically his whole campaign theme was that he could make better deals for the American People. So from the start he was very antagonistic towards previously-negotiated treaties like NATO, the Paris Accords, NAFTA, basically any agreement that requires some things from us. What he really wanted to do (my guess) is to renegotiate those treaties himself so he could claim to have won us more concessions from our 'enemies', and then he'd go down in history as a great treaty negotiator, a wheeler-dealer, which is how he's always wanted to be seen by others.