Some folks would call moving troops to Ft Sumter, & attempting to resupply them a hostile action.
And yet it was merely a standard, if delayed, re-supply of provisions for a U.S. fort. It is something that countries do, supply their forts via unarmed vessels if by water. And troops weren't "moved" to Sumpter on a lark, they had been pushed out of the other forts in the harbor. In other words utterly non-aggressive actions by the U.S., as those "some folks" know full well at some level below their agenda.