The flag he should have worried about in that battle was the three star flag waving on his Jeep, which drew fire.
“According to an eyewitness account, on June 18, Buckner had arrived in his command jeep which was flying its standard 3 star flag, to inspect a forward observation post. Visits from the general were not always welcome as his presence frequently drew enemy fire, which usually happened as General Buckner was departing. Buckner had arrived with his standard three stars showing on the front of his steel helmet and a nearby Marine outpost sent a signal to Buckner’s position stating that they could clearly see the general’s three stars on his helmet. Told of this, Buckner replaced his own helmet with an unmarked one. However, a small flat trajectory Japanese artillery projectile of unknown caliber (estimated 47mm) struck a coral rock outcropping next to the general and fragments entered his chest.”
But cool story about the rebel flag. God forbid that a general come up and now scold Marines for something that made them feel a little more aggressive.
An old Marine who fought at Okinawa told me that General Buckner Jr. was killed by a Marine artillery round that “accidentally” fell short after the general’s staff kicked a Marine artillery observer out of his fox hole so that the general could get a good look at the battle. That is a good story, even if it is not true.