This is just a repository for Creative Commons content, and it doesn't even appear to force the content to be CC, just royalty free.

http://dig.ccmixter.org/licenses

The business model here is a group of people have volunteered to maintain a shared opt-in repository and indexer so that musicians who want to release their content under a CC license can easily do so. There's no exploitation happening, unless you broadly consider Open licenses like CC or the GPL to be exploitation.

And if you do have a problem with CC licenses in general, it's probably better to take that up with https://creativecommons.org/

Do you say the same about people who write open source software? This is basically open source music, CC licensed. Just like in the software world, sometimes experimentation and sharing takes priority, not always, but it still has its place.

Some music isn't for sale. This is where you find that music.

People who record music are not desperate. Those trying to be the next popstar might be. Doubt there is huge overlap between those groups. You are more likely to see those on tiktok.

They put it up willingly. Why the hate on copyleft?

indie game developers who make nothing starting out get a possibly decent catalog with low effort, so its not all bad.