Yep, totally perplexing. All I can comment on is portion of his analysis that I know to be true. The SECDEF does have a 24hr, seven day a week security detail provided by the U.S. Army Protective Services Battalion (CID). If he went to Walter Reed, they were there with him. If he was in an ambulance, a PSB suburban was leading and following it. Secondly, he is correct that every senior leader in the government to include Four Star General Officers of each service are tracked by the NMC. However, that tracking usually doesn't grind to down to what street corner he or she might be occupying at any given time i.e Navy Secretary is in Norfolk or the Speaker is in New York. But normally the center would be aware if the SECDEF were in a hospital.I find it interesting how an individual posting from his bedroom seems to know more than the Washington Post, New York Times, CNN, MSNBC, Fox, etc. combined.
Therefore, until last week, I would have said it was impossible for the SECDEF's location to be unknown. I still pretty much believe that.
What I think is more likely is that some senior member of Biden's dysfunctional White House was informed and didn't manage to inform the President's direct handlers or spokespeople. It is then almost impossible to "correct" an initial press statement. It is interesting that there is not yet a hint of criticism of the SECDEF by the administration.