Very cool project with a very appropriate methodology. Would love if the project extended to include an assessment of potential mitigation strategies!

It's really cool to get human subjects for this study and N=38 is definitely quite nice. For more transparency on the statistics, you could add a standard deviation visualization and a statistical model e.g. finding that {human_evaluation} is statistically insignificant in the model {generated_by} ~ {human_evaluation} and the same for {persuasiveness} ~ {human_evaluation} * {generated_by}. The website looks very comprehensive and really interesting to show that you can do this impersonating a corporation. I guess there's a positive aspect to this for smaller business's interests to be heard as well, though the flooding of content on the message boards is a definite negative. For the next steps in this sort of work, you could literally just write this into a paper and submit it since you have enough of a sample size and the results show that it would be very hard to create a moderation algorithm that would accurately differentiate when even humans aren't capable of this. Your main defense might simply be to evaluate the frequency of messaging from similar IP addresses, an oldie but goldie. (edit; after looking again, I see you already included std.err)

Awesome project! The demonstration is convincing and shows a real conrete threat to the democratic process. I really like that you did a small survey to show that this is already a threat nowadays that should be mitigated.