It’s far better to reject someone’s story and add private notes than to do a lot of editing. That’s just ridiculous.
I do believe, though, that you are taking all of this way too seriously. There are gobs of other pubs on Medium to submit to or you can self- publish. I had this happen to me once. I pulled the story from the pub and never submitted there again. No need to dwell on it. No writer here on Medium has the right to control any editor’s behavior.