Unfortunately, you have been sold a bill of goods. I just hope that you are open to the possibility that the book(s) you are reading is not the WHOLE story, and willing to read MORE or what Lincoln himself said and did, and not just what these folks have "uncovered".
Truth is, there have long been books eager to expose the "real Lincoln". They often DO include REAL quotes by Lincoln... only they cherry pick, ignoring OTHER things he said, and often in the VERY SAME SPEECH that provide a different perspective. They also tend to pick EARLIER quotes (e.g., the Lincoln-Douglas debates) and not consider any evidence that his views CHANGED over time.
Here's a collection of quotes and perspectives, including those of Lincoln scholars and from people who KNEW him (like Frederick Douglass!) which may start to give you a more honest picture.
Since you cite the Lincoln-Douglas debates, I'd encourage you to read MORE of them (they are readily available online and in many books)... and wherever you see a NEGATIVE view of blacks expressed (which if you look closely is only a very few places), READ ON and see what ELSE he said at the time.
For example, CONTINUE the VERY quote cited (from Sept... 1858 Lincoln-Douglas debates) with the part the critics almost never make any mention of, even though it IMMEDIATELY follows what they cite: :
"...I have never said anything to the contrary, but I hold that, notwithstanding all this, there is no reason in the world why the ***** is not entitled to all the natural rights enumerated in Declaration of Independence—the right to life, liberty, liberty, and the pursuit of happiness. I hold that he is as much entitled to these as the white man..... he is not my equal in many respects—certainly not in color, perhaps not in moral or intellectual endowment. But in the right to eat the bread, without the leave of anybody else, which his own hands earn, he is my equal ... and the equal of every living man. "
** Just note how very different thing begin to sound if your FINISH the paragraph! NOT doing so is, sadly, characteristic of those who claim to "reveal" the "real Lincoln" that his admirers supposedly have hidden. No, sorry, Lincoln's biographers and serious historians have always acknowledged the quotes you are reading, but the ones distorting the record are those who STOP there.
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One historian's perspective:
"he was clearly reluctant to join in the commonplace assumption of the time concerning the racial superiority of whites over blacks. When such assertions were made by Lincoln, and these were rare, they were not spontaneously volunteered, and even when, as we shall see, these were wrung from him, they were defensive in nature, given the political contexts of their utterance, and they were qualified, rather than confidently categorical. This reluctance to admit of the inequality of the races was further exhibited in the following observation, where Lincoln clearly implies a belief in the categorical equality of all men, of all races and of all ethnic and class origins:
"I am not a Know-Nothing. That is certain. How could I be? How can any one who abhors the oppression of negroes, be in favor of degrading classes of white people? Our progress in degeneracy appears to me to be pretty rapid. As a nation, we began by declaring that "all men are created equal." We now practically read it "all men are created equal, except Negroes." When the Know-Nothings get control, it will read "all men are created equal, except Negroes and foreigners and Catholics." When it comes to this, I shall prefer emigrating to some country where they make no pretense of loving liberty - to Russia, for instance, where despotism can be taken pure and without the base alloy of hypocrisy." The Collected Works of Abraham Lincoln edited by Roy P. Basler, Volume II, "Letter to Joshua F. Speed" (August 24, 1855), p. 323.
http://www.martinspencer.org/AL.pdf p. 5
Another article, reviewing one of the popular books attacking Lincoln, responds to the question "is Abraham Lincoln a racist? thus:
"As President, Lincoln's struggle to end the Civil War and preserve the nation left him deeply sympathetic to the plight of the slaves and increased his belief in the need for racial equality in America.
"After seeing over 200,000 African-Americans volunteer and fight alongside Union forces, Lincoln dropped his support for plans to colonize freed slaves to Africa after the Civil War. In an 1863 speech, Lincoln stated, "there will be some black men who can remember that, with silent tongue, and clenched teeth, and steady eye, and well-poised bayonet, they have helped mankind on to this great consummation, while, I fear, there will be some white ones, unable to forget that, with malignant heart, and deceitful speech, they have strove to hinder it."
"To apply 20th century beliefs and standards to an America of 1858 and declare Abraham Lincoln a "racist" is a faulty formula that unfairly distorts Lincoln's true role in advancing civil and human rights. By the standards of his time, Lincoln's views on race and equality were progressive and truly changed minds, policy and most importantly, hearts for years to come."
http://usgovinfo.about.com/library/weekly/aa082800b.htm
"Historian David Potter wrote: "In the long-run conflict between deeply held convictions on one hand and habits of conformity to the cultural practices of a binary society on the other, the gravitational forces were all in the direction of equality. By a static analysis, Lincoln was a mild opponent of slavery and a moderate defender of racial discrimination. By a dynamic analysis, he held a concept of humanity which impelled him inexorably in the direction of freedom and equality."
"Historian Allen C. Guelzo noted: "When Frederick Douglass arrived at the White House in August, 1863, to meet Lincoln for the first time, he expected to meet a 'white man's president, entirely devoted to the welfare of the white men.' But he came away surprised to find Lincoln 'the first great man that I talked with in the United States freely who in no single instance reminded me of the difference between himself and myself, or the difference of color.' The reason Douglass surmised, was 'because of the similarity with which I had fought my way up, we both starting at the lowest rung of the ladder." This, in Douglass's mind, made Lincoln 'emphatically the black man's president.'""
http://www.mrlincolnandfreedom.org/content_inside.asp?ID=1&subjectID=1