On topic: interesting read. I'd never think these stories had so much dark side to them.
I got all 9 stories in 3 books at the age of 11 and read most of them, and was very happy with the stories, never noticing any of the dread the article speaks about.
Especially the Midwinter story was fascinating - we lived not that North, but in cold winter mid-continent, and the story was like looking out watching for the first signs of the spring, that eventually always comes, but you shouldn't celebrate any of those too early -- when day temperature comes above 0 in March, you know it's going to be freezing in the evening. (Later I was stunned with foreigners in our city complain of this March weather, call it "winter" and be depressed!)
A few years ago someone on social networks posted her impressions from reading them out loud to children -- that indeed it's depressive.
So I guess, the conclusion is that people make opposite meanings and moods of the same events.