"it didn't justify the actions of the Confederacy that began the war"
It was not actions of the Confederacy that began the war, but rather, inaction of the Union, specifically, Fort Sumter was sovreign Confederate territory, The C.S.A kindly asked the Union to remove their garrison from our territory. They refused, and after hearing that the fort was running out of supplies, they decided they were going to resupply the fort, and in doing so, they decided to violate sovreign Confederate maritime territory. The Republic of South Carolina, and more inclusively, the Confederate States of America, had every right to defend itself against what amounted to actions by a foreign power hostile to the nations existance.
The Union had a deed. The ground was bought and paid for. Sorry but that does not wash
Sumter was a U.S. fort build on territory deeded to it by the legislature of the state of South Carolina. What, exactly, caused it to automatically become 'sovereign confederate territory' without treaty or compensation?
After the Civil War, which they started, every one of them should have been given at least life terms for the horrors they & other traitors inflicted on this great nation.