'Socialist' 'Realism' was effectively the kitschification (for glorification of political power) of the Russian Realist tradition, which - as bad luck would have it - was actually one of the most interesting and artistically accomplished of the various 19th century Realist tendencies.
That's exactly the process that Robin is discussing. Because of my great fondness for Russian realism I like the aspects of socialist realism that suffered less than others from the kitschification, generally because of the skill of the artist in question rather than because some fields of the arts or areas of subject matter were somehow more immune to it than others (although I have seen it noted that socialist realist paintings of Lenin tend on balance to be less atrocious than those of Stalin, which comes as not much of a surprise at all).
Robin seems to think that what Gorky seemed to mean by his preferred term 'revolutionary romanticism' would probably have been more artistically fulfilled, but that's an effect of the fact that Gorky was a better writer and more honest than a lot of the people surrounding him and a lot of the other people at the First Soviet Writers' Congress to which Robin devotes Part One of the book. (The book focuses mostly on novels. Part Two is about the 'realist obsession of the nineteenth century' and spends a lot of time on Goncharov and Turgenev as novelists--there's a particularly vivid dissection of Bazarov from Fathers and Sons
--and Belinsky, Dobrolyubov, and Pisarev as critics, along with the requisite Chernyshevsky, Dostoyevsky, and Tolstoy.)
Robin spends the introduction talking about her personal background with Soviet film and literature and her genuine childhood love for this sort of thing. She's for the most part semi-sympathetic--more sympathetic to her former self than to the art in question--without being an apologist, although the 'insane dream' sequence at the end of Part One--which I'll type up if anybody is interested in reading it--is one of the most full-throated criticisms I've read in any book of this kind.
Rather delightfully, the American Realist tradition was also pretty accomplished and dynamic, and it also suffered the fate of kitschification-for-politics in the 1930s... though (mercifully) to a less extreme degree.
By the pre-kitschified form are you referring to (in visual art) painters like the Ashcan School, and by the post-kitschified form such as Norman Rockwell, or is my understanding of American realism constrained because I've spent so much of my life focusing on European and Asian art?