The issue at hand, if one stands back and looks at the big picture, is not about whether one should or should not share files, or copy them.
Remember the big furor ages ago about the illegality of copying tape cassettes? In short, it couldn't be stopped. No matter what the 'Big 5' or the RIAA are doing now to try and prevent copying and sharing, they will eventually lose the battle. It's inevitable. It's a matter of time. It doesn't matter whether you agree that sharing is ethical or not. The recording industry will change, is changing, for better or worse (depending whose side you're on) in the wake of digital music.
Of course, there are new paradigms springing up for purchasing music... but artists are going to have to (as they have for aeons) continue to rely on deriving their primary income on performing live. The Pandora's Box is open: people will forever copy and share their digital music, it's just too vast to control.
In the very near future, CDs will be obsolete, just as all previous forms of recorded music have become obsolete. Recorded music will soon be solely recorded, sold, stored, and shared in 0's and 1's... and in that form only. Even record stores will be unnecessary. It's all going to be online, and online only. (of course DVDs and DVD burners will remain, as a way for all music owners to store their libraries as they wish). Whatever concerns there are now about the legalities or illegalities of music sharing, are temporary. It's time for everyone to just accept the inevitable.