Can you imagine the outcry about international troops killing Rwandan civilians? Which most of the killers indeed were.
Perhaps, but even if international troops forestalled an international outcry by interceding only after solid evidence could be presented that 100,000 Tutsis had been massacred by "Rwandan civilians" that still would have saved 700,000 lives.
The killing went on for 100 days. If it could have been cut down to a 30 day or 20 day orgy of blood a lot of lives would have been saved.