“They let these men fight to the death for no reason.”
Nah, it wasn’t like that. The Japanese gained air and sea superiority before the Americans could marshal evacuation forces -which were few and far between. Mac didn’t fully see the threat in time to evacuate and besides there weren’t enough air or naval transports to remove the troops. If they’d tried many would have been destroyed by IJN and air. But they didn’t have the assets so the issue is moot.
The closet evac was Austrailia but there were hardly any planes or ships to do an evacuation with. At best subs and fast attack boats (like Mac used) could make it but there weren’t enough around to re-supply or evac the troops.
And FDR wasn’t setting strategic policy in Pacific in early ‘42, Mac was.