It’s clear that the choice taken was to quickly and simply take off a minor enemy unit, instead of taking some pains and running some risks to capture it.
This is not illegal, not a war crime, not even strictly immoral (in any case the immorality lies in starting the war).
It’s a matter of opinion whether it was worth the risk to show some humanity, in both the moral and strategic domains my opinion is that it was.
But expecting the current U.S. leadership to take the side of humanity in any decision where they can refuse to do it is a fools game.
We know who they are, and they prove it constantly, it’s useless to expect something better.
We, the world, needs them out of power as soon as possible, other than that we are just talking in circles.