Nonsense. Lincoln was sending supplies to the U.S. garrison manning the U.S. fort. He made his intentions to land supplies only and not men or munitions in a letter to Governor Pickens. Yet the confederacy chose to bombard the fort into surrender. That's what started the war and led to the death and destruction that followed.
Doesn't matter. The USA does not have the right to maintain forts on the territory of Foreign Nations who don't want us there, and more than China has the right to maintain Forts on US territory.
If a Foreign Nation does not want us on their land, we can't "send supplies" or troops or anything else. Morally, we must evacuate immediately, and nothing else -- after all, it's their country; not ours.