Even if this question seems like a general object oriented or code design question, I still find it relevant to game development, my point is if a question is about code design of a game engine, doesn't this make it a game development related question? game developers are software engineers in the end.
I migrated that question because it was on its way to being closed. Three people had already voted on it being closed as off topic here. Since I agreed that it was off topic here, I'd rather see it migrated than closed.
The criteria for questions like that is:
Would a professional game developer give me a better/different/more specific answer to this question than other programmers?
The rationale that we're all software engineers in the end isn't really appropriate thinking in this case. Stackoverflow is the place for those types of questions, we don't need to duplicate them here.
The current policy is:
Programming questions that aren't specific to game development are off-topic here, but can be asked on Stack Overflow. A good rule of thumb is to ask yourself "would a professional game developer give me a better/different/more specific answer to this question than other programmers?"
As you said, game development is just software development, and the question you linked is primarily a software engineering problem. Consequently, it is not necessarily likely to get a better answer from a game developer than a non-game developer, and the question is a better fit for StackOverflow.
Further, even though we can assume the focus of the question is on making a game, since it was asked here first, there really isn't much actual material in the question that is game-development-specific or related.