While I cannot provide a citation, The posts linked by the user seem to show most of them were by a single person whose profile became active just for posting on that sub.

Anecdotally, I used to mod a sub which suddenly became active due to a meme. I got messages from mods of different subs offering to help or asking me to make them mods. When I refused. the sub started getting reported for comments made by new users(Auto mod was not much helpful back then), The sub died out along with the interest on meme. If someone were to say there is a mod cartel on reddit, I wouldn’t doubt it one bit.

Purportedly, a former AHS footsoldier talks about some of what goes on:

https://www.youtube.com/watch?v=TG8xWJaJO-c

I've heard about AHS false flag operations many times, but i've never seen incontrovertible evidence of it. It feels like something that competent and technically savvy mods should be able to document. I'm not sure how many mods are even one of competent and technically savvy, let alone both.