Hadji became a derogatory name used by American troops to describe enemy fighters during the war in Iraq. The phrase "Hadji Don't Surf" is based on “CHARLIE DON’T SURF!” from the Viet Nam war movie “Apocalypse Now.” The phrase "Hadji Don't Surf" is a morale declaration that Americans are militarily and culturally superior to their Iraqi enemies.
Captain: "We've been ordered to secure that town TODAY."
Sergeant frowns: "Hmm... that will be a challenge, sir."
Captain smiles. "Yeah, but Hadji don't surf."