You got it wrong. Milosevic cannot be a war criminal as he was not waging any war. He did not commit crimes, unless you count normal anti-guerilla operations within territory of one's own country as criminal.
A. Pole, because most wars are not declared, international customary law makes war contingent upon a state of armed conflict, not a declaration of war. As you yourself stated in your post, the Serbs were conducting "anti-guerilla operations".
Of course, conducting anti-guerilla operations is not illegal and Milosevic is not on trial for "anti-guerilla operations". As the 60+ counts against Milosevic detail, deliberately causing the deaths of thousands of non-combatants is the problem, not fighting guerillas.
I must admit I was trolling a little with the post you responded to. Its one thing to be against the ICTY or Clark. It is entirely another to be for Milosevic. I just wanted to see who would scuttle out of their cyber spider hole to win the "Have a Slivo for Slobo " award.