“...(In terms of innocent blood lost, that raid was arguably the most expensive morale-building exercise in U.S. military history.)”
Although I’m sure you didn’t mean it, your post sounds like we had some culpability for the subsequent Japanese butchery, we did not. The horrors and atrocities committed by the Japanese in response to that raid and for the help the Chinese gave our downed American pilots is solely the responsibility of Japan.
That raid was brilliant and audacious, and that raid had a profound effect on the Japanese psyche and war strategy going forward. Their new fear of an attack on the Emperor and their home islands caused them to tie down many more resources than they had ever planned.
The Doolittle Raid was one of the best examples of why those Americans are truly in the running for the moniker, the Greatest (American) Generation.
Even as the US anticipated a vicious response against China by Japan, I agree that the crimes committed by the Japanese are solely the responsibility of the Japanese that committed them; I am in no way implying any guilt by association.
I would only point out whatever we gained by that raid was overwhelmed by the Chinese blood lost in response to it; had the prediction of 250,000 dead Chinese ever come up before the raid, it would have been immoral to carry it out, as it would have failed the proportionality test.