There simply isn't a real reason. There are many chemists and explosives experts who will testify to it. Your contact was taking advantage of your lack of experience in the field.

Note: You have convinced me to change my mind in several critical areas of security.

I wouldn't have done that without some background in security. Unless you convince me you have street creds in the liquid scenario the TSA is using to cow us, I'm simply not going to buy it.

The public are not children, except when the government wants to lie to them. @:-)

I guarantee that if you posted that "secret" you would shortly receive feedback to forever destroy sny confidence in your contact. That is how certain I am of physics and chemistry.