This was a matter of perspective isn't it?
Could they have not been runaway slaves? And as such therefore legitimate property to be recovered under UNITED STATES law? If I remember correctly the Emancipation Proclaimation did not repeal the Fugitive slave law did it? Nor had that law been repealled by any other act because slavery was still in existance in several state then still loyal to the Union. Besides that, why should the Confederate State Army reconize any law except the laws of the Confederate States?
On the other accounts the direct attack of a military force upon defenceless civilians for whatever military purpose was considered as being an outrage, even then. And would be what we now consider today as a human rights violation. It was the same as the Union navy firing incendary shells into the cities of Vicksburg and Charleston, or using the Church spires as aiming post for their pointless bombardments of those cities. These attacks by Sheridan, Sherman, Porter and others were made for no other purpose than mear punishment and had no real military value that could not have been accomplished by other means. The argument that they were done to accomplish some military objective are simple feeble attempts to justify this malviolent conduct.
I will point out that the Confederate Army during the Gettysburg Campaign assisted the citizens of a town in saving their homes from being burned by a fire started by the retreating Union army attempting to burn a bridge, but failed to do. And that the Confederate Army marched throught the town of Chambersburg PA. 3 times before it was finally burned in retaliation for Sherman and Sheridans actions in 1864.
Why didn't the Confederate Army burn the towns of Gettysburg, York, Hanover, Chambersburg, Fredricksburg, Maryland, Sharpsburg and others when they had the oppertunity?
The smartest thing Lee could have done on July 2nd, 1863 was to have gathered up his wounded and burned the Town of Gettysburg before withdrawing to a better defensive position and forced the Union Army to have attacked him, like Longstreet purposed. Burning Gettysburg while the Union Army sat on Cemetery ridge and watched would have set in concrete the victory they won the day before. But Lee didn't think that way and did not make war directly against civilians.