I would beg to differ on your conclusion that Grant had "no qualms about sacrificing" the men under his command.
That is a statement with no foundation as he expressed and exhibited the opposite. I agree with the inference that if Grant's tactics, though necessarily costly, had been employed by other commanders earlier in the war it could have potentially ended sooner saving more lives. I think one issue is that the term "butcher" in slang usage carries a connotation of carelessness in regard to and/or numbness to death and suffering. I don't believe this to be the case for Grant as he was capable of compassion, expressed remorse for the loss of life and sought to minimize casualties on multiple occasions for both sides. His wife Julia recalled that he never gloried over his victories instead there was just an abiding hope that it would prove to shorten the war. One can be pragmatic, calculated and dutiful without being devoid of compassion. The outcome of war is death and suffering, Grant identified what he thought was the best way to end that death and suffering in the shortest time possible to spare the most number of lives overall (within Washington's parameters). The argument that he could have done things differently tactically to reduce casualties and still bring about a swift end to the conflict is one that can and will continue to be debated. The other factor as mentioned here was the extent to which the political pressure from Washington to produce quick results to secure the re-election of Lincoln (Republicans) forced him to modify his strategy. In the end it has to be considered that Grant was not an island unto himself, he factored in advice and reports from staff, corp commanders, politicians, friends, spies and others when developing military actions. His actions, like any commanding officer, were subject to review and he was subject to dismissal if any of his actions proved untenable to the War Dept. & Washington.
Another factor that could be considered is war-hardening. This phenomenon was voiced by General Sherman who definitely took a harder line than Grant
"I regard the death and mangling of a couple thousand men as a small affair, a kind of morning dash — and it may be well that we become so hardened." This does not seem to have effected Grant as much as other soldiers in the field. He was naturally imperturbable but not unaffected. Those around him stated that human suffering effected him deeply and there are multiple instances of him showing compassion for both Union and Confederate soldiers on the field of battle.
Grant's view and expectations regarding the cost of the war evolved like it did for most. When the war broke out he thought like many that
"the rebellion against the Government would collapse suddenly and soon" and that their
"there will be much less bloodshed than is generally anticipated." After the shocking casualties at Shiloh the true nature and scope of the situation became apparent to him
"I gave up all idea of saving the Union except by complete conquest." During the Overland Campaign Grant had made some miscalculations about the state of the Army of Northern Virginia and Cold Harbor was an eye-opener. Grant would tell Halleck
"I now find, after thirty days of trial, the enemy...act purely on the defensive behind breastworks, or feebly on the offensive immediately in front of them....Without a greater sacrifice of human life than I am willing to make all cannot be accomplished that I had designed outside the city." This does not seem to be the words of someone who is completely callous to the loss of human life, although I'm sure if you read it a certain way you could see it as a solely tactical statement.
To: General Lee April 9, 1865
"By the south laying down their arms they will hasten that most desirable event, save thousands of human lives, and hundreds of millions of property..."
Was Grant more of a butcher than his superiors who approved his plans? Was he more of a butcher than the Confederates who shot the Union men under his command? Was he more of a butcher than the politicians who instigated the conflict? I think it broke Grant's heart and fired his patriotic passions when his country fell apart. I think he was willing to make serious sacrifices to restore the Union, but I don't think he lost his humanity in the process.
"...you cannot have peace and a division of our country. If the United States submits to a division now, it will not stop, but will go on until we reap the fate of Mexico, which is eternal war." -General Sherman
"War is cruelty. There is no use trying to reform it; the crueler it is, the sooner it will be over." -General Sherman
"Wars produce many stories of fiction, some of which are told until they are believed to be true." -Personal Memoirs of U.S. Grant
For more try this entire thread devoted to
Grant the Butcher