As I said, the argument for this being an ethically appropriate approach can be made from a Utilitarian or Consequentialist view point. That view becomes complicated by the difficulty of knowing what would have happened had alternative decisions been made (others have debated that point ad infinitum). It’s a partial knowledge problem.

It’s not my point though. Regardless of the actual trade in lives and human suffering between the two alternatives, a deontological viewpoint judges the rightness of an action by the action itself - no matter the outcome.

So that’s my point. The bombing of civilians (whatever the prevailing norms, and no matter the consequences), is always wrong, and can never be justified on the grounds of “it shortened the war“ or “it would have saved millions of lives”.

However, it’s not a simple and clear cut argument, and perhaps it can be justified in other ways. I reject the utilitarian arguments, but I’m open to considering other justifications.

Just goes to show you the silliness of how people use ethical systems. These systems are generalized out of example cases, not created de novo in concept-space and then applied unquestioned to every new example case.

The real world has many more real variables and tradeoffs than any ethical system could reasonably account for even abstractly. The systems provide a surface to bounce new cases off of, but IMO if an ethical system says it's preferable to pick near-certain death of say 1 million people (a mere 1.4% hypothetical casualty rate) over the certain death of 250,000 people, it should very obviously be discarded for that case.

In the real world every person performs acts they believe to be justified. If the ends justify the means, then all manner of evil acts can be accommodated. If we can’t turn and point at the destruction of entire cities with a weapon of unimaginable devastation and say “that is bad”, something is wrong.

No ethical system, including Kantian, says it’s better to pick a million dead over 250k. Kant says “you can’t kill 250000 people to save a million, and call yourself righteous”. A man can sell his soul to save his family but the price must be paid.