If you smell anything, it's your misunderstanding about the ownership/management of US airports.
Airports are not owned by the federal government. They are usually owned by municipalities or municipal/county/state joint ventures. So, depending on the airport, you might have any number of multi-jurisdictional agreements where jurisdiction is consolidated in a kind of "unified command" where police, sheriff and even state police all participate in the police activities. Or, the agreement might delegate a singular entity - like ATL's agreement with Atlanta PD, even though the airport is not located inside the city limits. Or, you might have a separate policing agency set up, like you see in the NY tri-state area with the "Port Authority".
Yes, screening passengers is a federal responsibility in most airports, but whomever owns/manages the airport retains primary jurisdiction. That doesn't mean the FBI can't assert jurisdiction when they want, because they do - frequently - but generally speaking, the lion's share of the manpower is local/state. For instance, if you shoplift from an airport merchant right next to the boarding gate, that's not a federal offense. But, if you slap the boarding agent, that might be a federal offense, and even though you'll be apprehended by the airport security/police force, you'll be turned over to federal officials.
We the People are pissed. Get used to it.