No, he hasn't. He told you exactly what you're missing. Your concern trolling is extremely transparent, and trying to game the system rarely pays off. It's time to start behaving like an adult. Second warning.
Not really. He only named a term, this "coordinate acceleration," but gave no indication of what it is or how it might be relevant. He suggested that knowledge of it will "blow my mind" without offering any details or context. It is a low content post which does not propel the conversation forward.
I do look forward to a robust discussion with Junker about this coordinate acceleration, which is a term sometimes used in general relativity circles. You see, we can discuss dynamic properties of spacetime in a fashion that is independent of coordinates. To achieve this, we use collections of covariant derivatives in mathematical objects called Christoffel symbols.
Unfortunately for Junker's claim, this is entirely irrelevant to the present discussion. The reason is because in the low-field limit there is no difference in the result you would obtain. That is, general relativity is commensurate with Minkowski metrics in conditions experienced on Earth.
It is odd to observe that one cannot even develop an understanding of coordinate acceleration without first assuming gravitation. Hence, it is quite suspicious that Junker would even suggest it in a discussion where he purposes to replace gravity with a new idea.
So you see, Pete, I am quite familiar with these things, and am not "missing" anything. And I enjoy engaging in these discussions in an adult-like fashion, but am not familiar with the term "concern trolling."