Yes, I agree that burning Gettysburg wasn't Lee's way, Lee didn't make war on civilians. Nor was it Confederate Army policy. They did eventually burn Chambersburg, Pa. and they would have been followed the example of some of destruction of southern citys, like the attempt to firebomb Vicksburg, by the North.
And unlike others when I put myself in Lee's shoes given the military attitudes that he would have been operating under I can understand him feeling like he had to fight the Yankees at Gettysburg on Days 2 and 3. July 1st was by no means a "Draw" Lee was on the field of battle as it was when the battle started. It was the Union Army which had withdrawn to Cemetery Hill. He had destroyed at least 2 corps of that Union Army on the 1st day, to the point the Reynolds 1st Corp was never reconstituted. His hope, I believe, was to destroy each corp as they came up. He did destroy the 3rd Corps and a large part of the 5th and 6th Corps the second day. And the 2nd corps was pretty badly mauled on the 3rd day. But that is all history.
Longstreet proposed to get between Washington and Meade and fight a defensive action. That would have been extremely unwise. But the south winning the political victory at Gettysburg would have caused Lincoln to have push Meade into a foolish act. Which was what Longstreet wanted, and knew would happen.
It may not have been necessary to have burned Gettysburg, but it would have sealed the impression of victory for the Confederates. Even you called the 1st days battle a "Draw" although the Union Army had been driven from the Battlefields south and west of Gettysburg and the town itself that they had been defending, was in Confederate hands. So had Lee withdrawn without burning Gettysburg, the object of their defence, the spin doctor would have still called the battle a Union Victory even though Meade wasn't going to attack Lee on the 2nd day anyway. So I see the burning of the town as being an important part of setting the trap that would have forced Meade to attack Lee in the mountain passes.
As I said that headline, "Army Routed, Town burned, General Reynolds killed, Lee moving on Cashtown, Chambersburg, or Harrisburg" would have sent shock waves and panic throughout the North all the way from New York, to Philadelphia, to Washington.
And remember I am talking about the political psyops war victory that was the objective of Lee's campaign in the first place.