I had a Conversation with My Wife piece stolen years ago. Content + photo, different title, same subtitle. Zero attribution. Ads every other paragraph, which was the point — it was a junk site that stole content off the Web so it would show up in searches. One of my Medium peeps tipped me off, there was a LOT of Medium content there, so somebody alerted Medium corporate and the site vanished or went dark.
For a few years after that, I (and a bunch of others) included a copyright notice at the end of stories. I usually added a humorous (?) twist because why not?