In a sectarian conflict, armed intervention is the only effective tool. We can wring our hands, apply economic sanctions, introduce stongly worded resolutions and congradulate ourselves for our moral stand but, for those poor souls in the line of fire, we can only observe and condemn. Unless we are willing to send real troops with real bullets (and kill real people), our protestations are empty gestures.
Condemning Ethiopia for intervening in Somalia is short sighted, even if their intervention is on the "wrong" side. Any nation that might experience a civil war, based on religion, should feel threatened and should act to prevent that war. Theocracies are, historically, intolerant and expansive. Nothing justifies injustice like faith.
What, then, is a moral people to do, in the face of atrocities? Intervention is not the answer unless we have learned nothing from a past adventures. Dictators abound and ethnic animosities are ingrained. We can not be the sword of justice, even if we, really, knew what the just side was, every time. We can, only, follow the example of Candide and tend our own gardens. It is not immoral to recognise limitations.