i don't really get this - if you use soulseek or any other p2p server then what you're doing is stealing (and helping others steal) music - it doesn't matter if you don't share the commercial releases of your favourite band or not as all the other stuff you do share makes you just as much a participant in illegal activities
i use soulseek a hell of a lot and so yes i'm depriving some artists from receiving my hard earned cash but i still do buy a lot of music, most of which i discover through soulseek in the first place. what i don't do is upload all of my CDs to my shared folders (at least not since the awesome audiogalaxy and its 'send to group' feature died out
)