Cheaper notwithstanding, there's two very good reasons to take fewer prisoners.
1. Fighting out of uniform puts civilians in danger. Under the Geneva Conventions, those who fight out of uniform in order to hide among civilians are a threat to those civilians, and may be executed on the spot. We choose not to do so, under our rules of engagement, but it is legal under the Geneva Conventions.
2. Those captured, except for the very senior leaders that are subject to harsh treatment, admit nothing and deny everything. Then, we're stuck with either throwing them back into the wild, or putting them in prison at our own expense.
Exactly my point.
But one can't "debate" policy issues any more. Because one side of the argument stands for mere obstruction and is, thus, incapable of arguing for an alternative.
Moreover, the minority "always knows best". Therefore, further argument is unnecessary.