AFIP clearly stated ONE YEAR AFTER the attacks that silica was a key aerosol enabling component. They are a named source, and they were charged by the FBI to analyze the spores.
Your fantasies about a massive conspiracy amongst USAMRIID scientists and the Whitehouse to pretend there was silica present is typical of a conspiracy theorist. I suppose you also believe the moon landings were faked and that explosive charges brought down the twin towers.
When you have to make stuff up to make a point, you are showing how desperate you are due to your lack of facts.
No one ever "pretended" there was silica in the attack anthrax. It was just assumed because the elements silicon and oxygen had been detected. That is NOT a conspiracy. It is a MISTAKE.
A conspiracy would be when someone claims that when General Parker and others say the Daschle anthrax was "pure spores" they are all lying and involved in some coverup of some illegal U.S. government bioweapons program, because the spores WERE coated with silica.
Not even AFIP claimed the spores were COATED with silica. It takes a unique level of stupidity to believe the spores WERE coated and everyone is lying about it.