Crusader skull used to spread disease and slash morale discovered by archaeologists

Ok, it’s a wild story and all but how do they come up with the theory that the skull was catapulted to spread disease?

How did the archaeologists decide it was used as a projectile in the first place?

How did they rule out the possibility of someone being decapitated during the conflict and either in the chaos of the battle or the following seven centuries the bones were separated from the body?

What is the difference between bodies which “had been disposed of in the pit and burned” and what happened to the bodies of soldiers that died on the battlefield and were buried by their own side?

At least the way it is presented it seems like a lot to get from some 700-or so year old bones.