Because it was Sherman's army that destroyed Hoods. Also, don't even try pretending like Sherman was better than Lee. It kind of distracts from the other points your making, and makes them sound less valid by association.
Um.... George Thomas was the Union commander at the Battles of Nashville and Franklin. 1) Sherman actually won his portion of the war. 2) He understood what modern warfare was. 3) He lost a lot fewer men as a proportion of the whole than Lee.
Lee wasn't the genius he was made out to be, and the scholarship on this has been pretty solid for the past 25 years or more. The Confederacy's best commanders were Stonewall Jackson, James Longstreet, and Nathan Forrest. Lee was a very charismatic man with very good subordinates who had the good fortune to go up against a run of incompetents. Lee didn't learn from his mistakes like he should have--he made the same mistake at Malvern Hill he made at Gettysburg, and less dramatically in several places in between. He lost more men as a proportion and as a number in the Seven Days' battles; he made the decision to fight at Sharpsburg and lost; even during his greatest victory, Chancellorsville, he lost nearly 20% of his men! Hooker lost about 12%. Gettysburg was one cock-up after another, and since Jeb Stuart did exaclty the same thing during this campaign that he did during the Sharpsburg campaign, it can't be blamed all on him. I mean, there's no question, were I a soldier during the period, I would not want to have been a soldier in the Army of Northern Virginia. It was far more dangerous than the alternatives.