To be fair, though, this experiment was stupid as all fuck. It was run on /r/changemyview to see if users would recognize that the comments were created by bots. The study's authors conclude that the users didn't recognize this. [EDIT: To clarify, the study was seeing if it could persuade the OP, but they did this in a subreddit where you aren't allowed to call out AI. If an LLM bot gets called out as such, its persuasiveness inherently falls off a cliff.]
Except, you know, Rule 3 of commenting in that subreddit is: "Refrain from accusing OP or anyone else of being unwilling to change their view, of using ChatGPT or other AI to generate text, [emphasis not even mine] or of arguing in bad faith."
It's like creating a poll to find out if women in Afghanistan are okay with having their rights taken away but making sure participants have to fill it out under the supervision of Hibatullah Akhundzada. "Obviously these are all brainwashed sheep who love the regime", happily concludes the dumbest pollster in history.