To me, it does. After all, it opens with a dedication making clear that the attitude shown within is also the author's:
This book is dedicated to all the seemingly anonymous folks, government, faith-based, or just plain charitable, who work out in the hills and hollers of Appalachia, tending to the people and their children who only think they can take care of themselves.
OK, negative attitudes towards Appalachians are pretty much a given in America -- "hillbillies" are the one group it's fine for even a liberal to hate -- but that doesn't mean it should be acceptable to cast off an entire group of people as incompetent -- or worse. Deutermann's words resonate antebellum attitudes towards African-Americans by their owners: "Why, we're doing our slaves a favor. They could never survive on their own." Deutermann, of course, certainly would not make such a statement about blacks (our culture now makes people mask such feelings) -- but he's blithely and openly willing to denigrate another whole section of the American population, and on as flimsy and sickening a basis.
Deutermann peppers his books with denigrations of Appalachians, each one a slap on the face:
"... All my guys have most of their teeth and can speak using the occasional two-syllable word." 
His accent was mountain, but not tree-stump ignorant. 
"Because the children have little value to a certain stratum of the population. As in, she was a' lookin' pretty damn good for thirteen, but then she done got her a damn kid hung on her. And if it was her daddy who did the hanging on, then the child become disposable." 
This much is true: there's a great deal of snobbery towards Appalachians, especially among those who have moved to the mountains from elsewhere (and there are many of those, these days). Ignoring it in a book set up in the hills of western North Carolina would be as bad as ignoring the racism that, even today, permeates American society. But Deutermann is not simply presenting the attitudes he finds; he is actively promoting his own.
The question remains, however: do Deutermann's (or any author's, for that matter) attitudes have an impact on the value of the book as a work of art? Personally, I would like to be able to answer, "No." But I am as human as Deutermann, and I bring my own prejudices into my reading, just as he does into his writing. As a child of Appalachia, I cannot honestly remove myself from reaction to the author's attitudes any more than an African can to Joseph Conrad's when reading Heart of Darkness.
The plot of Spider Mountain revolves around the nefarious activities of one "Grinny" Creigh, matriarch of a nasty clan in a remote North Carolina county adjacent to the Great Smoky Mountains National Park. Detective Richter's attempts to shed light on her activities are complicated by the fact that the local sheriff is also her brother and that state and federal authorities are reluctant to get too involved in local affairs. There are plenty of vicious dogs, fires, shootings -- and even a lynching and an attack by a wild boar. This is a suspense novel of the James Lee Burke variety: tough, tough characters facing down enemies of equal strength and greater nastiness. It lacks the sadness about violence and the recognition of its consequences, however, that raises Burke above so many others of the genre.
Read the rest of Marred by Attitude and decide for yourself, is Deutermann guilty only of elitism, or is there a tinge of tribal / racial smugness here as well?