I mean, I get lying to get a hostage back, but that also entails throughly burning that bridge.
The Administration might have been so dumb that they thought they could continue these peace talks without Korea bringing this up at least once.
I mean it suggests more so that these "peace talks" are the Trump admin secretly conceding to their demands to get a 'big PR win" on the surface and to create the illusion that their master negotiators have gone in and solved actual problems.
They're just making shit worse but it's all for short-term gains.