It's likely that the CSA and the locals were acting on rumors rather than gathering reliable intelligence or waiting until the situation cleared up.
Toombsy was right when he counseled against attacking the fort -- if he in fact did -- and wrong when he tried to justify it.
But reading the document makes me wonder if he wasn't lying when he said afterwards that he objected to the attack at the time.
A previous attempt to resupply the fort was made with only a single ship. Sending several gunboats and a large transport with riflemen aboard implies strongly that you are going to reinforce. That, and General Scott's order which said they were going to reinforce is enough to convince a reasonable man that this is indeed their intention.
Besides this, the Lincoln administration had already been stringing them along about giving up the fort, and so they just didn't trust him anymore.
It's likely that the CSA and the locals were acting on rumors rather than gathering reliable intelligence or waiting until the situation cleared up.
MONTGOMERY, April 10, 1861.General BEAUREGARD, Charleston:
If you have no doubt of the authorized character of the agent who communicated to you the intention of the Washington Government to supply Fort Sumter by force you will at once demand its evacuation, and if this is refused proceed, in such manner as you may determine, to reduce it. Answer.
L. P. WALKER.
They were getting intelligence from someone.
Toombsy was right when he counseled against attacking the fort -- if he in fact did -- and wrong when he tried to justify it.
But reading the document makes me wonder if he wasn't lying when he said afterwards that he objected to the attack at the time.
A man can believe both things, especially if he wants to believe both things. I have no doubt Toombsy thought it was a mistake, but afterwards he reconciled himself to believe Beauregard had no other choice.