As an Event Store Cloud user, I can be invited to different organisations as a member so I can log in to the console and look at their stuff. Not infrequently, those organisations don't remove me from their list of authorised users, but I don't really want to remain member of their org, and have access to their stuff.
As a result, those membership remains, and there's no way to leave the org.
There must be a way for a user to leave any organisation where they are members, unless they are the only remaining member.