[Aries]

Is the (Relative) Tuneful Conservativism of Prokofiev of Shostakovich the only positive thing to come out of Stalinism?

Possible. But I'm not sure how necessary the stalinist methods really were. Shostakovichs symphonies No. 2 and 4 for example made before Stalins terror are good works too and his tuneful 12th symphony was made after stalinism. The ideal of socialist realism in the USSR had a good influence, but I'm not sure how much the terror did in addition. On the other hand some extraordinarily tuneful works like The song of the forests would probably not exist without stalinism. But I rather want to emphasize the positive role of socialist realism or russian culture instead of stalinist terror.

Imagine if the 3rd Reich had lasted as long and a German composer of similar stature had stayed (unlike Hindemith). We would be faced with the same dilemma.

As far as I know composers were not forced nearly as much to write in a specific way in Germany as in the USSR. Instead jewish and too modern composers were not performed. Composers like Richard Strauss, Hans Pfitzner, Carl Orff, Wilhelm Furtwängler stayed in Germany. But their style was romantic/conservative before and after, so I didn't see that politics changes their style.

In America there were Samuel Barber, Bernard Herrmann and others at the time who also wrote in a romantic style. It overall was not really the time of modernism.

Overall I think it is a more accurate view of history that the romantic era ended at around 1950 instead of 1900. Before 1950 avant-garde composers were a minority not as important during their lifetime as historiography want to make us think today.

Should we feel guilty for this?

No. We should never feel guilty for our taste. Such who deny their taste should feel guilty instead. I maybe share much of my taste with Stalin and Hitler. It doesn't make my taste any worse. The musical taste of Stalin and Hitler really wasn't the problem.