Clarence Thomas arrives at hating substantive due process through an originalist perspective. But I believe he also views it’s roots as coming from the white supremacists Supreme Courts of slavery and the confederacy. He views it the same way those men read white supremacy into the constitution and dehumanized blacks in their rulings to keep them from equal rights, which was a very political take during a polarized time between abolitionists and slavers.
I could be mistaken I’m still learning about his perspective.