The fact that a song may be out of print but available as a free download doesn't make it any less stealing to make use of that download. You ask from whom are you stealing? For starters, the artist who wrote and recorded the song. He/She gets no royalties from your download. It's not the artist's fault that the song is out of print. Should she/he be further financially penalized because Capitol Records (for instance) decides to delete his/her catalogue? Your argument sounds like a rationalization for why its okay for you to rip off fellow artists. Think about it for a while and I'm sure you'll see the ramifications of your actions.
If a singer or musician chooses to put their music on the web for free, that's one thing. But the type of downloading you're refering to is stealing, plain and simple, until you decide to start personally sending royalty checks to those whose art you're pirating.