I don't need to make up what "AFIP saw or did". AFIP said they (or Detrick) saw an "unidentifiable substance" (it's difficult to call something an "unidentifiable substance" unless you notice it's presence in the first place). Then AFIP identified it as silica. They gave data in the form of publishing the data for silica that they used as a reference.
Beecher said there are no additives - but he doesn't give his source and provides zero data. He admits he has performed zero work himself on the analysis of the powder.
It is perfectly clear from Richard Preston's book "The Demon In The Freezer" that the "unidentifiable substance" was the "goop" they saw oozing OUT OF the spores under high-magnification on the Transimission Electron Microscope.
But the spores they took to AFIP for examination under the EDX were not the same spores with that "unindentifiable substance". They were evidently smart enough to realize that the EDX would pick up the chemicals used to kill the spores, so at AFIP they used dry spores which had been killed with radiation.
The facts are there. You just have to pay attention to them, and not just assume everything which disagrees with your theory is wrong or part of some conspiracy.
Ed