Because this would have been evidence of armed/uniformed combatants at the scene, some of whom would have been known to the Serbs.
But if the idea is that the KLA removed the bodies of their combatants, that nukes the theory held by many that the murdered farmers and villagers were really fighters.
Which reminds me, the normal KLA procedure was to evacuate & bury their own dead--not to leave them for the Serbs--I'm sure Wraith is familiar with that. Which again, further supports the non-combatant status of the dead villagers.