Because it's irrelevant. That's why.
Whether I'm a retired space shuttle pilot or a student in a lowly Cessna, my responses remain the same.
You want to know whether to give them credence by determining if you think I'm important enough. If Sully mouths the words, they must be true, because after all, he made a forced landing once. If Joe Blow mouths the words, the same identical words, they have no meaning, even though it's the same data, the same words, because Joe Blow doesn't have the qualifications that float your boat?
The words stand, and so does my point, which is correct, and true. I realize that perhaps you can't address the subject intelligently, and thus want to address me, instead, but that doesn't change the subject, my point, or the accuracy of my comments.
Have you something to contribute to the thread?