I think the court is wrong on this one.
The saliva of an HIV-infected man who bit a police officer doesn't constitute a deadly weapon or dangerous instrument under state law...Yeah, I know, key words: Under State Law.
They need to change their laws if not their judges.
Last I heard, somebody can be infected with HIV due to saliva. Saliva, in this case, is a deadly weapon. More deadlier than that 'real' looking squirt-gun somebody may have used to rob a bank with and has been subsequently convicted of a deadly weapons charge.
I've also heard (not sure when/where) that somebody who is highly acquired in one of the martial arts (karate, boxing,etc...) can be charged with 'deadly weapon' enhancements that a layman my not face. If true, I'd say that an HIV guy falls under the same logical category as to his saliva and other personal fluids.