This shouldn't surprise anyone at all.
First off, most Republican politicians/appointees are propped up by the military-industrial complex. So of course they aren't about to seriously push for peace. Money has always had influence, but especially today since people can donate unlimited money to campaigns and politicians. Our politicians are too bought to do anything about it.
So this whole idea of peace in North Korea, or anywhere else, from the Trump administration has always been complete bullshit.