First, you can't put "Mein Kampf" aside, but even if you do, "The Turner Diaries" is there, at Amazon, for anyone to purchase. Last I checked, that book supports the elimination of ALL blacks.
Now. If Amazon is asked to remove this dreck, and refuses, then the next step is a boycott - not a lawsuit to force them not to do business with someone.
Any legal means is fair and square to confront a moral atrocity.