Ah, but he did -- just not directly: "They formed a new alliance, but within each State its government has remained, the rights of person and property have not been disturbed." (emphasis mine)
There was really only one type of "property" at issue, of course.
And: "Through many years of controversy with our late associates, the Northern States" -- about slavery, of course.
And: "With a Constitution differing only from that of our fathers in so far as it is explanatory of their well-known intent, freed from the sectional conflicts which have interfered with the pursuit of the general welfare..."
The sectional conflicts were about slavery. And the the Confederate constitution primarily differed from "that of our fathers" by specifically protecting the right to own slaves.
And: "The cultivation of our fields has progressed as heretofore, and even should we be involved in war there would be no considerable diminution in the production of the staples which have constituted our exports and in which the commercial world has an interest scarcely less than our own. This common interest of the producer and consumer can only be interrupted by an exterior force which should obstruct its transmission to foreign markets..."
Davis is referring, of course, to cotton -- the production of which depended on slave labor. The south predicted that the abolition of slavery would result in "diminution in the production" of cotton, and the Confederacy hoped that the disruption to the "foreign markets" of England's textile industry, would result in British support for the Confederacy.
And: "We have changed the constituent parts, but not the system of our Government. The Constitution formed by our fathers is that of these Confederate States, in their exposition of it, and in the judicial construction it has received, we have a light which reveals its true meaning."
Again, one notes the changes pertaining to protection of slavery.
You might wish that Davis had said nothing about slavery -- but his speech is in fact suffused with the topic. He just was not honest enough to say it outright.
perfect