Is this really a contextually relevant oversight? Most terms do have multiple uses, but they depend a lot on the context for their applicability. I might be missing something, but I get the impression that the post's primary purpose is to highlight the problems with using the concept of obviousness here (and could plausibly be extended to do so in other circumstances where you're dealing with an audience to whom you can't immediately measure the inferential distance).

Using the concept of obviousness to signal that you possess or anticipate a certain level of knowledge has its, uh, obvious strengths, but I happily read the post as an explanation of how that usage might include some rather undesirable side-effects.

I'm not really concerned with where the post belongs in a broader sense, so I'm not challenging that statement, just its prior condition.