I have been asking this same question, why is the administration ducking this issue? The only explanation that I can come up with is that the administration does not want the the US public to be terrorized by the knowledge that Al Qaeda operatives actually have the ability to use biological weapons and dirty bombs. It is kind of like in the '80s when the gov't told us that latex gloves and condoms could protect against aids, they can't. The aids virus is small enough to pass right through microscopic wholes in latex.
I have been asking this same question, why is the administration ducking this issue? I think your logic might need a tweak.
You may want an answer, others as well. Lots of people want things they can't have.
Your want (lack of information) does not equate to "the administration ducking this issue."
I do have my tinfoil hat close by, though. Just in case.
LVM