Straight from their Terms of Service [1]:

  We can remove any content you post for any reason.

They also clarify that they have rules [2] that users need to follow. Also government takedown requests might be followed without even notifying you if the law prevents them from doing so.

So even if it wasn't a mistake, takedowns may still happen for whatever reasons and you need to take this into account before you start using the platform.

I really don't understand why some people complain about services doing exactly what's stated "on the box".

[1] https://policy.medium.com/medium-terms-of-service-9db0094a1e...

[2] https://policy.medium.com/medium-rules-30e5502c4eb4