Sheridan, Sherman and Grant would be considered war criminals by the standards of today - and also by the standards of 1860. The Union changed the rules of engagement to allow them to target civilians, whom they regarded as rebellious citizens of the Union. So they did it to their own people. Definitely not our government's finest hour.
Lee chose the wrong side, but otherwise was, arguably, the most decent of any commander in the war. Sheridan, in contrast, was an animal and far more deserving of the derision usually reserved for Lee.
Those who favor the removal of Confederate memorials while leaving in place those of Sheridan and Sherman demonstrate their lack of understanding of the Civil War, and betray the values that they claim to hold.