"A 650 mile amphibious assualt is not a "defensive" move."

What "amphibious assault" are you talking about? Are you suggesting that Lincoln ordered an amphibious attack upon Charleston?

"A defensive action is one that is made to protect territory from being taken by the enemy, like the guns surrounding Fort Sumter."

Exactly, which is why federal attempts to resupply Fort Sumter were defensive.

"Fort Sumter was not territory, it was a military device whose purpose was to protect the harbor and city of Charleston."

Fort Sumter was federal property.

"With those now in control of the State of South Carolina, Fort Sumter no longer had a military purpose."

Yes, but the seceded government of South Carolina did not command Anderson or his men. The federal government held the fort and wished to maintain it.

"His "preemptive and proactive move" to destroy Fort Moultrie's ability to function as a military position, and abandon it and all government property he was ordered to protect, was not a defensive move either, it was a retreat."

A retreat IS a defensive move.