If you don't like the word "elaborate" then feel free to choose another word. The point is that it's a detailed story about a specific time and place that they're claiming to be ground zero, and there's no evidence to support it. In fact, they've yet to find the natural reservoir for the virus to be able to definitively claim that it originated in another species, let alone that it did so through a specific species that existed in that specific place, then jumped. So, there's an obvious disconnect in the official story. What would you prefer to call it?

And, that it's a "common story" of how new diseases emerge has exactly zero bearing on whether this specific disease so evolved. You must know that form of argument is just syllogistically unsound.