It explains why the weapon would be weaponized ("Look how easy it is to make...") but not be resistant ("I don't want to actually _kill_ anyone") and the operational assault would be so bizarrely ineffective.
You can see him mailing them before the 11th and then eventually coming to the conclusion that his best bet, post 11th, was to dump all the notes and pretend it never happened. After the fourth (completely blameless) person dies he ends up killing himself.
The only problem with this theory is that it reads like every stupid conspiracy theory ever developed. The X files wouldn't even use it.