SAN ANTONIO — To say Marines, current and former, were stunned to hear that the Iraqi city of Falluja had once again fallen to black flag-waving jihadists is an understatement. Those reports have many veterans who deployed to Al Anbar Province questioning the purpose of their mission and the brutal battle that killed more than 100 Marines in 2004. Defense Secretary Chuck Hagel faced a direct question about the matter on Jan. 8 when he was visiting wounded warriors at the Brooke Army Medical Center in San Antonio. What would he say to those Marines? “You all did what you were…