Think of the fediverse as a federation of states, some bigger, some smaller, but all in the same ballpark. Threads had 10M signups just yesterday, which is more than the whole existing fediverse combined. Federating with them would be like the US adding China as a state - it would immediately be the biggest state by far, and would have the power to set politics for all others. And we know what sort of politics they would set, right?
Those bots wouldn’t pass the turing test, that’s for sure. One thing is pure spam like you’re describing, another is to be arguing with an AI (and losing) without even being aware that it’s an AI on the other side.
The problem with chatGPT is that it allows for automation of content creation.
Imagine a a single guy using chatGPT to control thousands of social media bots, who answer in a human-like way and are able to follow conversations and context, but who all defend the same point of view.
Or imagine a single guy controlling thousands of “local news blogs” that have a constant stream of fresh AI-generated content (both articles and comments), once again all pushing the same narrative.
That is the main problem with things like chatGPT, if not controlled - they allow anyone to create their own “troll farm”.
We know its Google.