[riffic]

the Pentagon is the name of a building (pretty much a very large bikeshed). I see the actual agency is named by the author as the Defense Department and one of the officials in question is a Defense Secretary. Interestingly, the bikeshed itself has its own spokespeople.

[jameskilton]

"The Pentagon" has been the nomenclature for DoD / DoW for decades. Everyone knows what it means.

[LambdaComplex]

Yeah, this is an incredibly common metonym.

[harimau777]

The Pentagon is a synecdoche for military leadership in the United States.

https://en.wikipedia.org/wiki/Synecdoche

[georgemcbay]

The White House is also the name of a building.

News sources have been using both building names (and several more I can think of off the top of my head) as short hand for the people who work inside of them for my entire life.

[ulbu]

there is also a figure of speech used soo often, called metonymy.

[loloquwowndueo]

It’s called a metonym. Look it up.

[simmerup]

yet it’s website is the department of war.

[mynameisvlad]

Officially, they're the Department of Defense. There was an EO signed last year that lets them use "Department of War" on all but their most official documents (since only Congress can officially change the name of the department).