I have been informed that the book the Wiener article is in is expensive, so here are some key quotes:

“By employing the language of race, Schenker adhered to the conventions of his day. Yet this did not reflect a belief in the strict doctrines of biological racism, as employed by racial theorists in Europe and America during the first third of the twentieth century. Schenker firmly rejected the concept of inherent biological differences among human population groups—a concept that would have been threatening to him as a Viennese Jew, continuously forced to negotiate the challenges posed by racial antisemitism both personally and professionally—and rarely used the rhetoric of racial science.

In Schenker Documents Online, a search for Schenker’s use of the term “race” yields fifty hits, three of which have an entirely different meaning: “race course” (SDO November [17?] 1911), “in a race” (SDO July 10, 1931), “ideas race ahead” (SDO August 30, 1914). Sixteen hits are for the “human race,” while on six occasions, Schenker refers to his own group, the Jews, once as an “alien race.” There are four references to the “Slavic race,” three to the “German race,” one to the “depraved [English] race,” and one to the “Anglo-Saxon race.”

Schenker rarely used the terms “black” and “white” as modifiers for races. In SDO, a search for “black” yields one hundred forty hits, but many of these are descriptions by the editors. There are many instances in the editorial descriptions and Schenker’s writings of such terms as “black ink,” “black-edged [writing paper],” “black material,” and “black market.” A search for “black coffee” yields sixty-two hits, more than one third of the total. There are no references to the “black race,” and only one reference to the “white race” in thousands of pages of documents (SDO August 20, 1914).

In the “literature” supplement to his edition of Beethoven’s Piano Sonata, op. 111 (1916), Schenker acknowledged the biological definition of race, only to turn it against the so-called “superior races,” castigating the “white Frenchman” and “white Englishman”(Schenker 2015, 21). Schenker’s specification that he derived his terminology from the German General Staff clearly indicates his intention to stigmatize “whites” in his damnation of both nations, not the people of color who served in the British and French armies.”“

Leon Botstein has suggested that Schenker responded to antisemitism by“question[ing] the idea of race as a category of explanation” (Botstein 2002, 244).

Schenker generally employed the term “race,” not as a biological category, but as a synonym for “nation.” In addition, he connected the concept of “nation” to language and culture, rather than ethnicity or religion.”“In “The Mission of German Genius,” Schenker defined his praise of the Germans as contingent on their appreciation for their language and culture, rather than on their supposed biological superiority.”“The fact that the German people can be
defined by language and culture forms the open and nebulous prerequisite for Schenker’s German nationalism, which allows, for example, ‘Friedrich’ Chopin to be included in the ‘series of great German masters.’”6 Schenker praised Chopin’s music for its Germanic qualities: “[E]ven though they [Chopin’s works] have not arisen directly from Germanness, they are certainly directly indebted to it” (Schenker 2004b, 20).”“On November 18, 1914, a few months after the outbreak of World War I, Schenker composed a diary entry in which he employed “race” and “nation” as synonyms, while defining national identity in purely linguistic terms.”