This depends, but not because of piracy. If you have to bypass DRM to download the music, you may be violating DMCA §1201 (even if you are otherwise allowed to use the music).

Edit: This obviously doesn't apply to GitHub, but might to YouTube.

When people torrent only a part of the file is being shared by all peers. Technically only the original seeder shared the whole thing and after a few seeders it’s a tiny portion of the file.

I think there's a difference between the laws for individuals and corporations. I don't think they're allowed to download either.

Downloading is illegal.

Any repo without a license disallows reproducing it in any way, which includes cloning it for business purposes.

The only exception is that public repositories can be forked on GitHub as new GitHub repositories. Forking doesn't give you a license to use or reproduce the code, though.

Never