It doesn’t support the idea that anthrax was easy to DIY. I have no idea to what extent LLMs make it easier, my only point is that the author implies that the fairly small damage caused by those attacks is because it’s hard to spread anthrax (the argument made in the linked paper). To the contrary, there was a ton of effort put into ensuring the anthrax didn’t spread.

I'm not sure what you mean that effort was put in to keep the anthrax from spreading. This stuff wasn't your grandmother's anthrax. The spores were small enough to pass through NATO biofilters. They were mixed with high levels of silicon, which apparently made them better at infecting the lungs. Sandia tried and failed 58 times to reproduce the high silica content, apparently. If anything, it sounds like the anthrax was intentionally designed to spread better.

It seems they were delivered in such a way to mitigate chances of other people/handlers getting sick, and they were delivered with notes that immediately told the victim what to do. Very weird story! But lots of indicators it wasn’t meant to be a big catastrophe.

I'm honestly surprised more wasn't made of it. There was no shortage of 9/11 conspiracy theories, but an anthrax attack was confirmed to come from a DoD lab, and they tried to pin it on Iraq initially, and... crickets?