Both HN itself and prolific HN contributor simonw get shoutouts in the article:
“The term [‘slop’] has sprung up in 4chan, Hacker News and YouTube comments, where anonymous posters sometimes project their proficiency in complex subject matter by using in-group language.”
“Some have identified Simon Willison, a developer, as an early adopter of the term — but Mr. Willison, who has pushed for the phrase’s adoption, said it was in use long before he found it. ‘I think I might actually have been quite late to the party!’ he said in an email.”
The first substantive discussion of the word here seems to be this: