The weird thing about Taney is that earlier in his life he apparently had a much more liberal view on abolitionism and anti-slavery activism. Famously, h e was a lawyer who defended a preacher for openly condemning slavery (in the presence of black slaves was what caused the arrest).
Here's a selection from that defense:
"Mr. Gruber did quote the language of our great act of national independence, and insisted on the principles contained in that venerated instrument. He did rebuke those masters, who, in the exercise of power, are deaf to the calls of humanity; and he warned them of the evils they might bring upon themselves. He did speak with abhorrence of those reptiles, who live by trading in human flesh, and enrich themselves by tearing the husband from the wife—the infant from the bosom of the mother: and this I am instructed was the head and front of his offending. Shall I content myself with saying he had a right to say this? That there is no law to punish him? So far is he from being the object of punishment in any form of proceeding, that we are prepared to maintain the same principles, and to use, if necessary, the same language here in the temple of justice, and in the presence of those who are the ministers of the law. A hard necessity, indeed, compels us to endure the evil of slavery for a time. It was imposed upon us by another nation, while we were yet in a state of colonial vassalage. It cannot be easily, or suddenly removed. Yet while it continues it is a blot on our national character, and every real lover of freedom confidently hopes that it will be effectually, though it must be gradually, wiped away; and earnestly looks for the means, by which this necessary object may be best attained. And until it shall be accomplished: until the time shall come when we can point without a blush, to the language held in the Declaration of Independence, every friend of humanity will seek to lighten the galling chain of slavery, and better, to the utmost of his power, the wretched condition of the slave."