Why is Frank Underwood opposed to slavery?

Question

Frank Underwood said of the Confederacy:

I personally take no pride in the Confederacy. Avoid wars you can’t win and never raise your flag for an asinine cause like slavery.

In another scene:

where he's confronted with a photo of his father wearing a KKK robe

he calls it "despicable".

Frank's view on slavery left me flummoxed. I thought Frank - a man with no conscience - would be in favor of slavery, or at least indifferent to it.

The best reasons I can come up with are his friendship with Freddie and real-life backlash if he sided with slavery. But if this is the case, then it would run contrary to his character. If so, then why leave it in the script at all?

Why was Frank so opposed to slavery?

Answer 1

Frank Underwood has developed a spirit of contradiction against his roots and his father.

Frank's father was a peach farmer in Gaffney, South Carolina, who died of a heart attack at the age of 43. Underwood has stated that he and his father had nothing in common whatsoever, and upon his father's death, he felt neither regret nor remorse. He also speaks about his father's cowardice, weak personality and drunken behavior.

Raised in impoverished circumstances, he found his hometown suffocating at the time.
_{House of Cards Wikia}

• South Carolina is traditionally a Republican State and he became Democrat.
• South Carolina was a Confederate State and he became opposed to Confederacy.

  South Carolina was the first state to secede from the Union (Dec. 1860), and was one of the founder members of the Confederacy (Feb. 1861). _Wikipedia

• As he moved to DC, he adapted to northern lifestyle and despices southerners. I didin't like much trips to his home State when he has to campaign.

  I grew up here, in the up country-- Bibles, barbecues, and broken backs. Everything gets just a little bit thicker this far south-- The air, the blood, even me. I try to make it down here at least once a month. Every trip is a reminder of how far I've come. I hated Gaffney as a kid, when I had nothing, but now I've come to appreciate it. It's not as suffocating as it once was, except when I have to deal with the sort of nonsense that makes me want to hang myself.
  _{Season 1, Chapter 3}

Also his opinion against slavery may not have been build on conscience, but on political and economical point of view: On Civil war, North States adopted an economy based on factories and waged workers as South States adopted an economy based on Slavery.