> > they used a non-pathogenic strain of anthrax
> No, check https://en.wikipedia.org/wiki/Matsumoto_sarin_attack
That's a different attack. I'm talking about their 1993 anthrax attack: https://pmc.ncbi.nlm.nih.gov/articles/PMC3322761/
Analysis of the 48 suspect colonies confirmed them to be B. anthracis ... This genotype was identical to that of the Sterne 34F2 strain, used commercially in Japan to vaccinate animals against anthrax.
They used a vaccine strain because they didn't know any better. Even members of the elite can make mistakes, especially when operating outside areas they know well!
(This was not the only thing that went wrong, but several others were also knowledge failures.)