Does site indie hackers use black hat SEO?

Hi everyone!

Working on my project Palitra I found some traffic comes from the site indiehackers.com
I started checking back links and found a strange link Reached Ramen Profitability - Indie Hackers where I saw that the post was written on my behalf. I was surprised!

After that I wrote a tweet and a post.

I sent direct messages to @IndieHackers and @csallen. Nobody replied to me!

I thought maybe it was a bug. I did some research and found 1500 links with the same text on behalf of other authors. I was shocked!

Any thoughts?