Title 41, Code of Federal Regulations, Subpart 101-20.3, here's the pdf.

http://www.osec.doc.gov/osy/npcsecurity/osypdffilest-zandsecuritymanual/title41.pdf

Had similar experience (not on this scale or w/ this org) at PJKK Fed Bldg.  Probably could have been handled better if event organizers had also coordinated w/ those whose job is to secure and protect the property.  It's been done before, but your article does not mention if this was done.  Also, I too, have a issued ID card and they still can tell me to leave.  I used to work there and probably know the people you mentioned.  Anyway, to conflate your negative experience w/ the current admin is a little hyperbolic.  Just me saying.  You do understand the govt's viewpoint, though, right?