And by explicit, he means explicit. They state their new nation is about slavery at least 4 separate times in a relatively short document, with black chattel slavery named as a requirement of any confederate state that was foundational, and could not at any point be outlawed. Their states had no "states rights" when it came to slavery.

The confederate States foundation was not a rejection of the US that happened to include legalizing slavery, it was was a rejection of the Union in order to forever legalize slavery specifically, as its primary aim, and they were not at any point shy about that fact in founding their slaver nation.

I was thinking about the sequence of events that led to the secession, not the justification for it. Of course looking at how the Conferedates justified the secession is another valid perspective that paints a much different picture. So you're definitely right in that regard.

And yes, we're both thinking about how the states' rights that were being disrespected were northern states' rights. That's just something modern slavery apologists don't want to admit because then their side wouldn't be the plucky underdogs rising up against oppression. I'm going to edit my earlier comment to make this clearer.