How the hell is a study on stanford.edu assuming posts on Reddit are genuine? That should be enough to get you kicked out of Stanford.

If it is the AITA subreddit (or one of many similar ones) it might not be that bad. It is after all dedicated to outrage farming, so there will be many human responses. It is just the original posts that are all baits, and it doesn't really matter if they are made by LLMs or as a creative writing exercise.

Though interestingly, the observed difference in assessment suggests (though does not prove) that sampled AITA posters are not one of these models. I guess it’s possible they have a very different prompt though…