OMG amen to all of this! I'm an editor at MuddyUm and Contemplate. I very rarely have any problems with anyone over my notes. Mostly what I flag is excessive wordiness. Also run-on sentences that need splitting. Sometimes reminding them it's best to open with action. It's just amazing how many writers open with, "X is Y." Many times the second sentence is the better opener.
I'm seeing less of it on MuddyUm submissions, I guess because I've edited the work of most of our regulars.
I did have one person go into a major pout, pull their work, and then write a hit piece about me. That was some time ago and I reported it. Personal attacks are contrary to Medium rules.
I've learned a lot as an editor, like how to couch criticism so it's comfy. Humor makes for a comfy chair.* It's also great for my stats because people know who I am.

"Who's getting the chair! WHO'S GETTING THE CHAIR!"