Fort Sumter was a "pretext" only in the same sense that, for examples, Pearl Harbor and 9/11 were "pretexts".
All had the effects of convincing all Americans that war had begun in earnest.
"Mr. President, at this time it is suicide, murder, and will lose us every friend at the North.
You will wantonly strike a hornet's nest which extends from mountain to ocean, and legions now quiet will swarm out and sting us to death.
It is unnecessary; it puts us in the wrong; it is fatal."[19]"
To compare Fort Sumter - no battle deaths - to Pearl Harbor or September 11 is inapt and unapt.
It is also inept.