If "Miles Routledge" is on a "shooting trip with the Taliban", he deserves anything he gets.
And if you make a habit of visiting "spicy jurisdictions", you deserve anything you get.
I say this not out of animus for you or Routledge, but if you knowingly and intentionally engage in risky behavior, you don't get to whine when something goes wrong.
Edit: I smoke cigarettes, which I know to be risky behavior. If I get lung cancer, I won't be whining about it.
Similarly, if Routledge's Taliban buddies decide they don't like him any more, and take a notion to saw off his head on video (a rather more likely risk than him accidentally being sent to Gitmo, IMO), that's on him.
Being buddies with the Taliban exposes you to the risk of them sawing off your head, or being taken prisoner as an unlawful combatant.
And no, imprisoning unlawful combatants indefinitely is not "illegal", neither under United States law nor under the international laws of war.
If you claim otherwise, I'm going to have to ask for a citation.
And it gets a downmod, rather than a citation. Hint: that means you lose.
And for very good reason. The states power should always be checked, at home or abroad.
This is especially important as these days wars don't end.
So far what I've got is a broader perspective so thank you.
It's fine to say you wouldn't but let's not go projecting.
[1] https://nypost.com/2021/08/18/uk-student-miles-routledge-fli...