The fires in Waco was started INSIDE the compound. Not by those assaulting the compound. Take that up in the conspiracy thread.
Even if that were true, which I'm not convinced it was, the cops were well aware that there were dozens of children in there, and that Koresh was believed to be insane, and that Koresh had warned that he would kill everyone if any attempt to breach was made. Knowing that, they broke down a wall using a tank retriever and inserted pounds of highly flammable, military-grade tear gas.
Again, they knew there were innocent kids in there. They knew Koresh was unstable. They knew Koresh had threatened mass suicide. So does it matter
who started the fire? It is undeniably obvious who was responsible for it.
Remember -- 21 children. Some as young as two. Innocent tots. The impatient cops ignored that and sealed their fate.