This isn't all that new as people have been employed to do exactly this very thing so all that's really happening here is that these people will be using AI to write their posts now.
The real problem here might be more that people place far too much trust in public consensus. Historically speaking, public consensus has a very poor track record. Far worse than any individual or organization I wouldn't trust.
An international team of researchers has issued a warning on the dangers of AI swarms with regard to the manufacturing of fake public consensus, noting that it might have already been happening.