If we (people on HN) like their 4 comments enough to vote them to the top, then it's up to us.
Same for their "submission history". I could not care less if it's comprised from their own articles on Medium. As long as people liked and voted for the stories to go on the front page, that's enough. If people on HN didn't like and vote for the stories, they'd be lost, like countless other submissions. So there's that.
I would have a problem if antirez, or idlewords, or PG, or whoever posted their own articles either. Why not? There's the upvoting of submissions to tells us whether those are good or not.
I also checked the submissions history of the person you refer to. 30 submissions in 6 years. Hardly clogging the pipes.
Besides, what they share in this post is regarding Medium, so is totally on topic. There's this, too.
What's this putdown for? Jealousy? Moral indignation? I don't really like the tone and the finger pointing.
Your comment seems more like an ad hominem than anything else.