I think the fallacy Nominull committed was the assumption that any complaint that something is confusing is committing the Mind Projection Fallacy because the confusion is really in the mind, when really, the complaint is about actual properties of the "confusing" thing that contributed to the confusion in the mind.

Though this is not quite the issue I was talking about in the post. It is more like what PhilGoetz was describing (which is not surprising, as that was a response to Nominull's comment). That is, Nominull did state how a detail of the fallacy described Phil's comment, but I think that explanation missed the point.