It's a little different. In one case, there is enough evidence to analyze, and the analysis is inconclusive. But here, by the standards of the profession, there isn't even enough evidence to analyze. By the expert's own standards, it's inappropriate to bring this analytical tool to bear on the question.
-- I'm not sure why an "audio forensic expert" would be needed at all. I do understand how the story feeds the sensationalism of the reporting. --
That's it, that's the reason. And, if this gets to a law court, to attempt to undermine the eyewitness - but I think the testimony is inadmissible in court, because, by the expert's own standards, he cannot form an opinion. Therefore, he has nothing to add to getting to the truth of the matter.
Outside of the courtroom, he is free to blow smoke and direct away from the truth - that's what he's getting paid to do.
I think we may have been talking about two different aspects. I was only talking about the 48% match. I think you may be talking about the 20 words standard, which the sample recording did not meet, and I totally agree, of course - not that facts require my agreement.