This comment is sorta like moving the goal posts. Shutting down a base is not the same as ordering a withdraw and giving up the real estate.
Lincoln could have withdrawn and given up the land at his own whim. It would have had no significant impact on the Union's ability to defend itself.
Evacuating Pearl Harbor and giving up the land would have been not only horrifically costly, it would have been seriously detrimental to US defense.
You have to remember that the normal condition of Fort Sumter was empty. Nobody was stationed there by actual orders until after the Civil War, and they only did that to make a symbolic point. Eventually those troops were withdrawn, and it has stood empty of a garrison ever since.
Fort Sumter was repaired and rearmed after the war, and was extensively reworked in 1897, remaining in service until 1947, when it was retired along with most coastal fortifications that outlived their usefulness in an era of missiles and jets. In all, over 70 coastal defense installations were decommissioned between 1946 and 1950, Sumter among them.
“Nobody was stationed there by actual orders”
Not the case. Anderson, as the senior Army officer on scene, had the authority to order his troops to a position that was more defensible. Sumter was more easily defended with 100 or so troops, than the open batteries he had occupied.