The point is that these ships did not have orders to attack Charleston as you claim in many of these discussions.
How you arrive at that conclusion is beyond my ability to comprehend. The orders clearly say force is to be used *if resisted* and "resisted" is baked into the cake.
The ships did indeed have orders to attack them. That's what "use force" means.
And just to clarify, the ships weren't going to attack "Charleston" as your statement above implies, they were going to attack the Confederate forces surrounding Sumter.