Furthermore, I agree that US and Ethiopian actions (aside from being illegal under international law) might have the opposite effect of fomenting (instead of discouraging) radicals.

Well of course: there's nothing these people are good at except fomenting radicals. They need them in order to survive, in the same way  that the crazy Israelis need the crazy Palestinians and the men of violence in Northern Ireland needed each other. Their power comes from the existence of a simple enemy. Without them they would have no reason to exist.