Muslim fathers forced to rape their daughters and Serbs forced to rape by their comrades. Two thousand years ago Mithradates, King of Pontus, having driven the Romans from Asia Minor, organised the Greek city states of the coast to massacre all the Italian merchants they could find. I have no doubt that Mithradates was not the inventor of this political tactic but 2,000 years will suffice. Getting people to fight from fear and guilt is a very old tactic. Ethnic cleansing has a crude logic.
Systematic rape seems at first to be a pointless outrage.
Unless outrage is the point. If you are a Serb who has stood by while fellow Serbs have raped your neighbours daughter you do not expect him to return and shake your hand when it is all over. No you expect him to return with a gun and you had better have a gun too or flee Bosnia altogether. While it would be difficult for the Muslims to compete with the Serbs not all atrocities are Serbian propaganda. I don't think it was wishful thinking.