It's not quoting the nested quotes so I'm just not going to quote at all.

But regarding Lincoln speaking against slavery the contents of those speeches are highly relevant.

There were many different positions in the anti-slavery camp. These ranged from:

(1) Abolitionist

(2) No New Slave States

(3) Don't allow expansion of slave states outside the bounds of a particular treaty.

There are many people of that time period in camp (3) who made anti-slavery speeches, so without providing specific contents of speeches it is hard to place where Lincoln was at a particular period of time along this spectrum.

I think much of the problem is media literacy and the difference between good and bad sources. This is a very tricky subject in the humanities as with the creeping in of postmodernism even the journals are often full of biased opinionated pieces supported by unsound or invalid deductions. For example something as simple as showing evidence for a->b, then showing evidence for not(a) then concluding not(b), when in fact a implies b shows nothing at all about what not(a) implies. The reduced popularity of peer review and standards makes it very tricky to assess the difference between good and bad sources. Basically we often get to the point where in media literacy we teach students "X, Y and Z are not good sources for information because of R1,R2 and R3", then in every high school class we encourage the use of "X,Y and Z" as sources.