You might be right, but I would understand "I'm not surprised" as a way to introduce an opinion or an analysis, rather than as something like "It would be dumb

You might be right, but I would understand "I'm not surprised" as a way to introduce an opinion or an analysis, rather than as something like "It would be dumb to be surprised". Though to be fair, I had a similar reaction when I saw the title as the commenter of your link (more like, "Well, no shit!"). I still find the conversation and the points of view of everyone here interesting, I would not be here otherwise. I would be particularly interested by someone who would indeed be surprised and offer an analysis I could not see.