Dude, all of this is irrelevant until you can actually prove that 'true knowledge' of music actually exists. You've yet to directly answer my point, and I'm on the verge of just giving up after having repeated it four times.
Okay, I'm latching on to what you are saying. Nothing can be "better" than anything else without a "better"-determining standard, even though X could be objectively more harmonious/melodic/whatever than Y.
Let me ask if I'm getting this. Back to the SSBM example, it would be incorrect to say "Marth is 'better' than Roy", but it would be correct to say "Marth is better at winning than Roy". Is this along the lines of what you're saying?
Essentially, yes. I mean, I'm not really sure how you'd be able to truly judge whether Marth is better at winning than Roy, since so much of it is player skill and style and such, but that's the idea.
The way tier lists are constructed is mostly just by looking at tournament results. It is assumed that on a tournament level, the characters are being played to their fullest potential. Since people that play as Marth place higher than people that play as Roy, this is used to support the argument that Marth should be higher on the tier list than Roy.
Of course, the assumption itself is flawed, and that's why tier lists are constantly changing. For example, Jigglypuff used to be in the above-average tier around 11th place or something, but now she's in 3rd because pros figured out how to be better with her.
But back to the music discussion, I guess we can come to the agreement than it is silly to say one song is better than another. In fact, I think we can even agree that it's silly to say that anything is better than anything else. Simply because the word "better" needs to be addressing some kind of purpose.
And if that's settled, my follow up question would be, can we make objective claims regarding the specific qualities of music? Like, "X is more rythmic than Y"? Or even as far as "X is better to dance to than Y"?