The document is real.
Not a shill, just spoke the truth. My sauce would dox me, so no thanks.
I see it's starting to show up online now.
https://news.usni.org/2021/01/12/message-from-joint-chiefs-on-u-s-capitol-riot
Would the US Naval Institute be good enough sauce for you?
https://news.usni.org/2021/01/12/message-from-joint-chiefs-on-u-s-capitol-riot