he's shown his willingness to use these things in the past. he's killed more muslims than the US ever came close to doing. If he'd kill muslims with such a relish, imagine how quick and easy it would be for him to kill Jews or Americans.
Tons of VX? Ebola? Yah. return em to the stone age. let em start civilization from the stone age again. It'll keep em out of trouble for a while at least.