I will quibble about some of the statements in that article. For my source, I quote Robert Greenberg from the Teaching Company and his series of CDs on Shostakovich (which I highly recommend).
The 7th Symphony is, yes, about the oppression of Hitler and his Fascism, and about other kinds of oppression as well (read Stalin and Communism) but Stalin was too dense to get it. The mundane theme in the first movement that is repeated for about 15 minutes, getting louder and louder until it is overpowering, is all about Communism. Shostakovich began this symphony even before the Leningrad seige.
I love his work for that hidden tension in it that resists Communism. Shostakovich carried a toothbrush and cake of soap every time he left the house. You never knew who might seize you and where you'd end up. Many of his friends were killed by Stalin. It was a terrifying era.
Thanks so much for the post.
I believe the party line (both literally and figuratively) was/is that it refers to the approach of the German army. But that doesn't really make sense. I believe you hit the nail on the head describing it. It perfectly expresses Stalin's regime of insanity and terror in general and maybe particularly the madness of th "Great Terror".
And that's not to say that even when not "Great", Stalin's terror was anything but terrible.