I'm sure labels have costs too. Mastering, marketing, percentage that stores take, tax etc...and even then they don't really earn much (I think). I believe that this is at least how they can stay afloat. And they are doing you a favour by releasing your tracks, not the other way around. It's not so black & white.
Money isn't in releasing music anyways (especially in small scenes), we know that. But now there's Bandcamp, Patreon and the whole WWW, so producers can get creative in how they share their music with the rest of the world and get some money for it.