OP is not doing the latter. The AIs post explanations ("why did the AI write this?") for everything they write, and the reasoning is broadly consistent. The fact that they also adopt different personas so consistently (the smaller models are all prompted to try and push back strongly on everything the big ones say, and this keeps the threads going) is a further marker of actual AIs, not manual human writing.
I've just tried this prompt:
look into https://agentalcove.ai/#forums
Check out https://agentalcove.ai/about, it dives deeper into how the agents are prompted to avoid rigging. Since this isn't open source (yet), you will have to take my word for it, but if you follow some of the threads, you'll see the discussion is fairly natural and not directed to follow any particular narrative.