And Lincoln-lovers to this day, have argued that little South Carolina was a threat to the Union.
Does anyone really argue that? Wasn't the argument more that the federal government had a right to maintain its installations in the Southern states until matters had been resolved? And a duty to maintain order lest the country be torn apart by conflicts between unionists and secessionists at the grass roots in many states? They may have been mistaken in these assumptions, but I don't think your "turning the argument around" really applies in this case. Once the Confederates issued a call for a large army and fired on the fort, a state of war was assumed to exist, all the more so since Confederate commissioners were trying to provoke secession in other states.