"but the fact is that mp3s are getting music to many people who wouldn't have paid for it anyway"

Hmm.. The other day I found a set of keys to a persons Lamborghini. He never uses it - it just sits there in his garage. so I stole it. Which is OK since he never uses it. I wouldn't usually steal things, but since I foudn the keys.. that makes it OK.

That's the logic you are using. Think about it.