I think there's a fundamental problem on Medium with the term "Editor." First, most Medium publication editors have no formal credentials or relevant experience. I've worked with about three I'd happily exempt from this statement - three that could (and possibly do) earn upwards of $65/hr for their skills, and I got them for free, here. Lucky me!

That does not include anyone who relies on Grammarly or any other automated AI "grammar helper" to do their job. It doesn't include anyone without formal education in the language being written in, nor anyone who thinks there are not acceptable regional variations in spelling and grammar between the UK, US, CA, AU, and other English-speaking parts of the world.

What we have here, mostly, are unpaid volunteer helpers. Some of them are writers. A very few are editors. The fact is, you get what you pay for. I would simply have withdrawn the piece from the publication with "thanks for considering, but I have decided to submit elsewhere" (it's not as if they've invested anything in your work - or plan to pay you for it - so simultaneous submissions and last-minute withdrawals are hardly "taboo").

In defense of all large publications on Medium - Medium is also rife with entitled writers and writers who are incapable of reading the most basic submissions guidelines. Submissions guidelines are an awesome way to weed out authors who just want to see their name in lights and claim they were "accepted by [some publication]" as if that weren't still tantamount, here, to self-publishing.

Take heart, though - the larger the publication, the less likely your work is to be seen and read and generate any revenue at all for you. Publishing on your own, or in a smaller pub that generates little drama and controversy, is probably your best bet.