Hasty generalization fallacy.
Despite the notion that the difference is negligible, there is quite clearly a difference. It ensures that detractors cannot assert that his appearance in one game is a reason for non-inclusion. That is the only relevant aspect of speculation that I intended to address when I mentioned "prevalence." I do not believe that Hyrule Warriors contributes a lot regarding his inclusion in Smash; however, I do believe that it might be a reason that more are advocating for him, hence the reason I typed the post in the first place.
Correct, I was not around when his original, stronger popularity was rampant. I never insinuated that this makes him particularly likely either, not sure where you are getting that sentiment unless that was not directed at me. There are many differing forms of logic, I am not quite sure which form you are specifically alluding to, but a "logical speculator" in the context I provided is one who is aware of the merit of the character, one who understands why they may or may not be included, one who supports the character based on a certain rationale... the standard definition of the word. Ghirahim has more potential reasons for inclusion than any other Legend of Zelda candidate sans Impa. Therefore, I have deduced that a "logical speculator" would be more open to the prospect of Ghirahim once the trophy quiz theory was affirmed through Robin's confirmation.
This brings us to the next point, "baseless inference." I am not sure what your definition of "baseless" entails. But it is certainly not the traditional usage of the word...