No, all you have to do is read their own words. Its hard for us to put ourselves into their mindset, because that mindset doesn’t exist anymore here, but they actually believed their system to be a righteous one worthy of defending and worthy of propagating. They say so quite clearly and quite proudly.
This does not mean every southerner was evil or every northerner was righteous. The truth is actually more interesting, as good men fought on both sides. When you see that many of the generals in the south along with their soldiers were devout Christians, that only makes the whole thing that much more interesting.
I never understood how Christianity and slavery were compatible or justified.
I agree.
I understand a proposed amendment to the Constitution--which amendment, however, I have not seen--has passed Congress, to the effect that the Federal Government shall never interfere with the domestic institutions of the States, including that of persons held to service. To avoid misconstruction of what I have said, I depart from my purpose not to speak of particular amendments so far as to say that, holding such a provision to now be implied constitutional law, I have no objection to its being made express and irrevocable. "
He is of course referring to the Corwin Amendment.
"No amendment shall be made to the Constitution which will authorize or give to Congress power to abolish or interfere, within any State, with the domestic institutions thereof, including that of persons held to labor or service by the laws of said State."
I interpret his words to mean that the continuation of slavery in the United States of America was not an issue for him, his government, or the Northern states who voted to pass the Corwin amendment in both houses of Congress.