I don't know why people decided to jump on this one specific project but there have been numerous replacement frontends for HN published over the years, and put on Show HN. And clones of HN. And datasets of HN comments.
I can't speak for other people, but I commented here because the person I replied to shared their project and then in response to concerns about it copying other people's content, tried to position that first as being OK because they'd offer opt-out, and then said that was viable because if it were opt-in the site wouldn't be possible.
I can't speak for other people, but I commented here because the person I replied to shared their project and then in response to concerns about it copying other people's content, tried to position that first as being OK because they'd offer opt-out, and then said that was viable because if it were opt-in the site wouldn't be possible.