But even in your case of letting all the spies be killed to save one civilian, it would in the end result in more dead civilians because if a country does that to its own spies, nobody will want to be a spy for them anymore

Ridiculous from top to bottom.

First, you're taking the U.S. at its word that there was anyone on its side in real danger. There is no reason to trust the U.S., and many reasons to think they're lying -- they're fighting a proxy war against Russia, after all.

Second, it's laughable to take the premise of additional intelligence possibly endangering some spy and turning that into "this would kill all U.S. spies."

Finally, the U.S. has fucked over countless lackeys in the past and will continue to do so. Dying for your country is what these people already signed up for, and there will be more meat for the grinder whatever happens to a spy here or there, because of a million reasons, but mostly because who the hell is telling recruits about some active spy that gets burned?