[DoodleDawg]

Well then, for what were they fighting? What necessity compelled them to send husbands and sons to the South to be killed?

To suppress the armed rebellion started by the Southern states when they fired on Sumter.

[DiogenesLamp]

If Lincoln hadn't sent ships to attack them, they wouldn't have fired on Sumter. They were prepared to give Major Anderson as much time as he needed and he was about to evacuate. Then those ships showed up and the Confederates had already received word as to their orders from their spies and sympathizers in the Navy.

They already knew why those ships were there, and what they represented. They represented a forthcoming attack, according to the orders which had been sent to the Confederates.

Had there been no ships with attack orders, there would have been no attack against Sumter.