The identity may (officially) be unknown, although the source of the Anthrax is internal--pretty much has to be.
But use a little logic instead of just emoting, because you hate the terrorists.
This was NOT the sort of job they'd do. Say what you will about them, but they typically don't lay on an operation unless it's going to be big.
Obviously 9/11 was big. USS Cole was big. Khobar Towers was big. The African embassies was a big op. So on and on, all the way back to Beirut.
They carefully mark their targets, train, and carry out the operation, so as to make the maximum "noise" and garner big publicity.
The silly little Anthrax thing was what a kid with a pipe bomb mentality would have done had he been able to get "weaponized" (another garish, silly label; in this case it just means "spores") variety of Anthrax.
It was a domestic nut, a Ted Kasczinsky type. No doubt about it.
Who is emoting? Using logic and coming up with a good guess is one thing. Your theory (and that is all it is unless you are in the official inside track) is a good one. It does have one weak link though. How does a 16 yr old or a 'crackpot' get ahold of weapons grade anthrax? One report called it "more sophisticated than anything ever seen before.".
I could emote on the way you trivialize the anthrax attacks. Did Kasczinsky tie the Postal Service in knots and cost the taxpayers who-knows-how-many millions of dollars? Did he scare the livin' crap out of millions of Americans? Six people died, not two or three. But those are just numbers. Well hey, mathematics is an emotional subject.
Either you're a friend of Leahy's and you know more than the rest of us or...