1) Who said that? - "Say" might be an understatement. General George Gordon Meade roared that sentence, already angry because Warren had moved without order and Wright had been too slow.
2) When (during what battle) was it said? - It was said on June 1, 1864 during the Battle of Cold Harbor.
3) Who was "he"? - He was General William F. "Baldy" Smith.
Think me weird but that somehow makes me like Meade even more.
1) General George G. Meade
2) Battle of Cold Harbor:
Things in the Army of the Potomac became even more unsettled, and Meade began to show signs of stress and fatigue. Theodore Lyman recorded that Meade ‘was in one of his irascible fits to-night.’ Meade complained that Maj. Gen. Gouverneur Warren and his V Corps had pushed too far forward without orders, adding that Wright was too slow, and that he wished the corps commanders would act for themselves and stop leaning on him. In the midst of all this ranting, an aide to General Smith arrived to report that his commanding officer was in serious need of ammunition and transportation, and that Smith ‘considered his position precarious.’ Using profanity he seldom indulged in, a clearly exasperated Meade roared, ‘Then, why in Hell did he come at all for?’
1. Who said - General George Meade
2. What battle - Cold Harbor (said on June 1, 1864)
3. The “he” - General Baldy Smith (as Meade originally told Smith’s messenger, Capt. Francis Farquhar when Meade was told “Smith had arrived with little ammunition and no transportation, and that he considered his position precarious”) - “Smith was so angry when Farquhar reported the quote back to him, that he included the incident when he wrote his official report two months later”.
Searching for George Gordon Meade, by Tom Huntington, page 288.
George G. Meade (1815-1872) said that of William F. ‘Baldy’ Smith (1824-1903) whose XVIII Corps had arrived at Cold Harbor exhausted, low on ammunition and without adequate transport after a lengthy march due to a mistaken order. <Theodore Lyman, With Grant and Meade from the Wilderness to Appomattox. (New York: The Atlantic Monthly Press, 1922), p. 138.>