I wouldn't be so sure about that. Reddit might not retain sole ownership, but they certainly seem to own a copy: https://www.redditinc.com/policies/user-agreement

  Except and solely to the extent such a restriction is impermissible under applicable law, you may not, without our written agreement:

  license, sell, transfer, assign, distribute, host, or otherwise commercially exploit the Services or Content;

  [...]

  By submitting Your Content to the Services, you represent and warrant that you have all rights, power, and authority necessary to grant the rights to Your Content contained within these Terms.

  When Your Content is created with or submitted to the Services, you grant us a worldwide, royalty-free, perpetual, irrevocable, non-exclusive, transferable, and sublicensable license to use, copy, modify, adapt, prepare derivative works of, distribute, store, perform, and display Your Content and any name, username, voice, or likeness provided in connection with Your Content in all media formats and channels now known or later developed anywhere in the world.