I think when you're accusing a country of war crimes, it's important not to be hyperbolic. If you inflate what is going on, it just allows your enemies to do exactly as you say and go "Well TECHNICALLY it's not genocide". You want to nail them to the wall for what they are actually doing so they can't escape.

We all know that ethnic cleansing will probably deteriorate into genocide, because people will not want or will not be able to leave, but to "jump the gun" (sorry) just gives them a way out.