mysterious01 was offering to artificially keep ANN threads on the 1st page via fake conversations within those threads, while the OP was offering his services to make a single post (or a very small number of posts) by way of engaging in a discussion with other users. I think there is a very big difference between these two things.
What is the difference between them you think?
Mysterious01 was offering the service to keep ANNs on top by regularly posting in them, and He had a list of users who would do those postings to keep bumping ANNs to get paid by Him (Mysterious01). Now OP (Text) was one of the users to do one or more than one posts in a thread by a way of engaging but with the purpose of bumping it only to complete his task and get paid for it. What is the
very big difference in these two that you are talking about?
I don't think what the OP was engaging in is not all that different than what "community managers" are frequently paid to do.
Community managers are given the responsibility of managing those threads. They don't just engage in there to keep their threads on top, but they do their work in the thread which they are supposed to do. You can't compare these two situations at all.
They won't just let you take charge of a surgery in an ICU as that is not your work and you are not allowed to do it. Now you can't say that if the doctor can do it, why can't I?
I would also point out that in the past, users have been given incentives to post in the thread of what they are advertising.
That thing was abandoned later on when admins started to lock down the threads having such a rule in them. So we better live in present, without doing the things that are not allowed now but were done in the past.