I don't know what that has to do with what I posted. Both houses of Congress specifically stated in their July 1861 resolutions that the war was not being waged to interfere with established institutions in the seceded states (i.e., slavery). Were there similar resolutions by Congress in WWII saying the war was not being fought to save Holocaust victims? If so, please post them.
And then there is this from the New York Times of April 6, 1861, in an article entitled "The Issue at the North." Bold type and the second paragraph break below are mine.
… There is no disposition, on the part of the great body of the Northern people to wage war upon Slavery, or to countenance any aggressions upon Southern rights.
But the question assumes a very different shape. Slavery has nothing whatever to do with the tremendous issues now awaiting decision. It has disappeared almost entirely from the political discussions of the day. No one mentions it in connection with our present complications.
No man, anywhere in the North, proposes for a moment to interfere with Slavery in any Southern State. No man proposes to exclude Slavery by Congressional action from any Territory. No man proposes to interfere in any way with the execution of the Fugitive Slave law, or in any way to interfere with the equality of the States, or the rights, privileges and immunities of the citizens of all the States, in regard to the institution of Slavery.
The Times back then lived in a fairy land, I think. They still do, of course.
War changes things and people.
In early December of 1941 Americans, both as individuals and as a government, still considered aerial bombings of cities to constitute war crimes, and among the greatest examples of the evil nature of the German and Japanese tyrannies.
A couple of years later we were cheerfully and intentionally killing millions of German and Japanese civilians. Similar attitude changes happened very rapidly with regard to unrestricted submarine warfare.
In 1861 it it true that most northerners had no desire to destroy the institution of slavery. The number who did steadily increased throughout the war, till by 1865 this opinion was very nearly universal.
Of course, even then it was for many, perhaps most, based more on a desire to punish the slaveocrats who started the war and caused so much suffering than on a feeling of brotherhood for the black man.
I do not see how you can quote a prewar newspaper article as representative of Union opinion throughout a four year war.