viz.

In two instances you've mischaracterized Dr. Gribben's intentions here.

You wrote that Gribben published this edited edition such to create a volume he didn't find "personally offensive"; as Gribben has stated in his introduction and elsewhere, Gribben's initiative didn't involve his personal feelings about the language in the book. Rather his interest in publishing this volume was for meeting a need suggested to him by actual high school teachers who wanted to teach Twain's books in their classrooms, but were themselves forbidden to do so by concerned administrators or parents. Gribben isn't offended by Twain's language; he's trying to help teachers get Twain back into the classroom after it's been "banned by omission" by school boards.

Second, you state that Gribben created this volume because he believed "his rendition of Twain would be more appropriate in the context of the classroom." Again, this is false. Gribben, a Twain scholar who's taught these works himself, has no compunction against the unedited version of Twain's works being taught in classrooms; his edited volumes are for teachers who feel an edited version is necessary for their specific classrooms. Gribben is making no judgment that this is a more "appropriate" version of these books; instead he's published these volumes to offer another option for teachers who might want them.

There's nothing wrong with disagreeing with the publication of these books or how they should be used, but one should be careful not to ascribe nefarious intentions where none exist.