The problem is that exposing which country is working with the Biden/Obama administration would justify Senate Democrats and Republicans calling for a war with that country. What the incoming Trump administration is attempting to do is avoid that war.

Or, if the country sending the drones is an ally, like Great Britain, that poses an entirely different set of problems. For one, it would signal to our enemies throughout the world that the United States is so weak, even our own allies are moving against us.