Though I am all for extraction, maybe screwing with their minds or humiliating them. I agree, the basis of the Geneva Conventions is that they are persona non grata on arrival, they are only fit for a firing squad.
Unfortunately by taking them “prisoner” that does by law imply they might be held as one.
However if we simply kill them at will, without mercy methodically and machine like, I think that like all personalities that people have they would simply acknowledge that we are the masters and they are the servants.
That I believe is the psychology of the mainstream muslim community. These people are like wolf packs if you show any remorse whatsoever they swarm and pounce. We have to show absolute dominance, not hearts and minds because their hearts and minds will change when the Jihadists start bombing again.
Exactly why allowing the enemy to achieve "prisoner status" should be very carefully avoided - unless there is a SPECIFIC person and purpose to grant "prisoner status"...
We're there to destroy the enemy -- not to incarcerate him.