You asked:
> Do we have many examples of cases where countries have held US soldiers or commanders of allied nations captive without repercussion?
And clear answer to that such a year yes, with dozens of examples off the top of my head that I was unsure in what context you might assume it was true.
> UK and France are quite weak indeed
Not in comparison to NK and especially not historic NK they aren’t. Have you ever actually studied foreign events, history, or looked into foreign militaries etc? You have such a distorted viewpoint I just find it baffling. In terms of traditional military NK has 1/3 the UK’s population, vastly worse industry, outdated equipment, minimal ability to move beyond their borders, etc. In a head to head fight they would lose badly.