CFA Jr. led an African-American regiment in the war and had a lot of complaints about his troops. He was typical of some other Northerners who went to war for idealistic reasons and became disillusioned when the world didn't correspond to their ideals. Oliver Wendell Holmes Jr. was another: he never got over his war experiences.
Plus, the Adamses identified with the older America before the Civil War. They saw a lot of corruption in the country after the war and this made them nostalgic and drew them closer to the Southerners who had been so dominant politically in antebellum America. They could see political and financial corruption up close in the North and assumed the South was free from it.
You can see the same dynamic in CF's brother Henry, but Henry never went so far as CF did in glorifying the old South:
I disagree with my brother Charles and Theodore Roosevelt. I think that Lee should have been hanged. It was all the worse that he was a good man and a fine character and acted conscientiously. These facts have nothing to do with the case and should not have been allowed to interfere with just penalties. It's always the good men who do the most harm in the world.
Right, thanks.
I can't always keep the different Adams straight in my mind, but do remember that both John & John Quincy were... what's the word, "Southophiles"? "Australophiles"?
They admired Southerners, especially Virginians like Washington & Jefferson.
But the Johns also opposed slavery, where possible, and it seems like in CF Adams Jr. the two opposing feelings (pro-South, anti-slavery) worked themselves out rather oddly.