How are you guys not getting it?
What I'm saying is much like the philosophical idea of "true knowledge" vs. "head knowledge." It's been a while, so I forgot the actual terms, but hopefully these suffice. "True knowledge" is that which is objectively true. "Head knowledge" is basically true knowledge run through the filter of our individual perspectives. Since no one is omnipotent, no one knows what "true knowledge" actually is. But as we learn more, we try to make the overlap between our head knowledge and true knowledge as high as possible.
This can be used to compare the perspectives and opinions of two different people. Let's say Person A knows 10% there is to know about music, and Person B knows 1%. These numbers are just arbitrary for arguments sake. All that really means in the context of true knowledge is that Person A's perspective is 10x less "foggy" than Person B's. If I were to put money on who's "head knowledge" overlapped with "true knowledge" the most, I'd bet on Person A (even though there remains the possibility that Person B actually has more true knowledge overlap).
That's why I've been careful to use words like "probably" and "likely". There is no way to know with 100% certainty the objective quality of music. But as we listen more, learn more, etc., our views grow ever more clear. That's why I said that I probably "know" more (i.e. have more true knowledge overlap) than someone like my mom.