It is a prohibition against IMPERSONATING LAW ENFORCEMENT -- a thing already illegal pretty much anywhere.
READ the language excerpted, don't just take someone's word that it "bans satire", ... it doesn't.
I loathe the TSA and want them disbanded. I am also totally paranoid about any govt overreach that infringes on ANY rights, including Freedom of Speech. BUT ....... this ain't it.
in a matter that is reasonably calculated to convey the impression that the wearer of the item of apparel is acting pursuant to the legal authority of the TSA (Transportation Security Administration) or Federal Air Marshal Service.