Of course he did, he wanted to defend the anti-slavery statutes. But he saw the consequences of Dred Scott and saw that the logical sequel of that decision, when applied to states' antislavery laws, meant that slavery would be legal everywhere, not just in the Territories but in the whole United States.
What you are saying is that slavery was legal in the territories because according to Taney and a majority of the court the Constitution said it was.
Don't put words in my mouth. The holding was that a) Scott never ceased to be a slave, not even when he was in Illinois or in the northern Territories above the Missouri Compromise line, and b) Congress had no power to deprive citizens of their property rights absent an amendment.
The sequel was that slavery was legal everywhere.
The implication was that the state antislavery laws were unconstitutional.
Do you agree?