I agree with you, but in a different way.
Perhaps this was set up as a test by the network to check out the lethality of the existing spores and delivery method before a full bore attack is made.
In this case, both the deadliness of the available anthrax and effectiveness of whatever delivery system was used may have been proven to somebody's satisfaction. As there seems to be no indication the victim knew he was attacked or infected, it makes this event all the more scary. He may have been an unknowing guinea pig for an anthrax beta test. After all, why play such a big hand if you don't know the stuff works the way it is supposed to the first time? Why go to all the trouble and exposure if for some reason the batch is not lethal?
This may have been a surreptitious attack done exclusively to check the deadliness of this batch of particular anthrax, which is now awaiting distribution through watever means. It is now proven sufficiently deadly to take the next step, whatever that may be. If it were, then the main batch is probably awaiting H-Hour in The Plan.
... /tin foil hat ...
Unfortunately, if that is the delivery mechanism it is likely already discarded in a landfill somewhere.