Well, that "doctrine" was largely based on deciding that the 14th Amendment had nothing to do with ensuring equal rights for former slaves and their children, b

Well, that "doctrine" was largely based on deciding that the 14th Amendment had nothing to do with ensuring equal rights for former slaves and their children, but rather was enacted to turn the US into libertarian paradise. See Holmes' famous dissent in Lochner in which he said "The Fourteenth Amendment does not enact Mr. Herbert Spencer's Social Statics."