Many German soldiers in WWII surrendered to Americans because their fathers/uncles/etc told them how well Americans treated THEM in WWI.

The "kill them all" mentality would only stiffen an enemy's resolve. If your enemy takes no prisoners, why NOT fight to the last man?

Also, there are those pesky concepts of 'war crimes' and 'morality' to worry about. . .

Not to beat a dead horse, or in this case 46and2, but the easiest counter-argument to his point is the military concept of “casualties”

Armies count “casualties” (dead and wounded) as they are in effect unavailable for future combat until they recover (or in the case of the dead, that tends to be fairly permanent).

When you take a prisoner, you are in effect creating a near-permanent casualty for the enemy. This is critical, as every soldier off the battlefield is one less soldier to face in the future.

Going back to that 400k prisoner figure, if we did not take prisoners it is more than likely that our own casualty figures would be 400k more dead, or worse (attackers tend to take more losses than defenders).

I think not losing a half-million citizens is more than enough reason to take prisoners, wouldn’t you say?

I often stood on the ramp while nuke loaded B-52 after B-52 went rolling by. And I knew the same scene was playing out nationwide. And in missile silos. And submarines.
Looked as if there was not a lot of concern for prisoners. Or anybody on the receiving end, for that matter.