Walt
That is true. Even scholars who want to agree with DiLorenzo's thesis find the book very sloppy. Go here for a review. But those who disagree with DiLorenzo really haven't yet had their say in the press, so the final verdict will be even more negative.
The theses DiLorenzo presents aren't new: they go back to the post bellum writings of Confederate apologists. Historians have long since disposed of most of his charges, and they'll disprove them again, when Di Lorenzo's book shows up on their radar screens.
Of course Lincoln had been a politician and was a man of his times. I don't know of anyone who's studied the period who seriously thinks otherwise. Admitting that the man was human shouldn't be taken as some great new revelation. It's the beginning of understanding, not the end.