I will recognize them as valid Supreme Court decisions, which I disagree with. But as much as I may disagree with the court's decision that doesn't make abortion illegal just because I proclaim the decision bogus. Likewise you can howl and rage all you want about Texas v. White and claim it's bogus until you're blue in the face. That doesn't change the fact that unilateral secession as practiced by the Southern states is illegal and will remain illegal until the Constitution is amended or a future court overturns the decision.
As for Scott v. Sandford, defending that one is a Southern thang.