The anthrax strain was a highly weaponized one.
The only possibilities that make sense is that a person in the military/industrial complex wanted to wake us up to the threat; or,
Saddam gave a very small sample to al-Qaeda and he decided to not give them any more after the US starting beating the war drum against Iraq as well as Afghanistan.
I believe that was its purpose. The targets were obviously going to make the news.
How is it that they even discovered it was anthrax for Stevens EXCEPT that the other letters had been received. I think we're missing a piece.
You could do it at home.