The movie "The Network" called them humanoids. We now call them NPCs. Basically, they are people acting under the influence of propaganda. There could be AIs, but propaganda is much easier to assume. Reddit could be defrauding their advertisers by adding AIs. I doubt that they would be able to keep that a secret for very long. It could also be that Reddit's user base no longer participates like it once did due to certain types of users leaving or platform changes that affects behavior. If I knew that moderators were likely to remove my post, I would probably post less.