I'm glad you discovered it and reported it. It's absolutely unacceptable for a writer to do this, and if they do that on Medium, who knows what they would do elsewhere. It's entirely unethical. What a nerve. Don't these people have any ideas of their own. There are tons of topics to write about, yet they've got to lazily and unethically copy someone else. You're right it's a black mark against their reputation and trust and it's at Medium's mercy if they take action against them. Can't say I would be sorry if they did, as this writer knowingly did something fraudulent without conscience. It wasn't a mistake or error, it was 100% deliberate to benefit at your expense and take credit for your work. It's clear you are a very ethical writer and respect the value of writer's work and that they deserve credit for their work. I can't stand people doing such horrible things. It's identity and intellectual theft.