"Somewhere in the middle" is one of three possibilities if you reduce everything to a one-dimensional line and pick two points. Even in the rare cases where an oversimplified single continuum expresses the best solutions to address a problem, there is little reason to assume that two point alternatives aren't together in being the wrong direction away from the optimum.

However, I really think golemotron was just referring to when a trend becomes a default that no longer needs to have its case made in new situations. Like assuming middlegrounds are implicitly correct, or cargo culting, it's just a form of assuming there are shortcuts that make understanding the mechanisms of success or doing actual analysis are unnecessary.

Your understanding of the middle ground fallacy does not accord with the rest of the world's: https://en.wikipedia.org/wiki/Argument_to_moderation

The middle ground fallacy is the idea that given two ideas, the truth lies somewhere in between them.