https://medium.com/policy/medium-terms-of-service-9db0094a1e...
You own the rights to the content you post on Medium. We don’t claim ownership over any of it. However, by posting or transferring content to Medium, you give us permission to use your content solely to do the things we need to do to provide Medium Services, including, without limitation, storing, displaying, reproducing, and distributing your content. This may include promoting your content with partner companies or services for broader broadcast, distribution, or publication.
This is identical to the ToS for any hosted blogging service such as Blogger or Wordpress - you have to give them a license to your words for the site to do their job.