It seems that way. Cloudbet are probably not involved in shilling and the two scenarios you listed are most probable in this case. Shills and scammers in general try to infiltrate threads in various ways in order to gain an air of respectability as they progress towards their ultimate goals.
I don't think Cloudbet is behind the shilling, though. It's an old casino, they have had so many campaign in the past, and they definitely know the forum rules. This particular ring of scammers or bumping farm just replies other threads to;
1. Increase post count.
2. Make their accounts undetectable to the snoops by covering their tracks in legitimate threads.
Why there is any reason for Cloudbet to pay money for posting to attract attention to the thread if they even do not answer in this thread?
The casino already exists 9 years and have a lot of users.
I play casino and monitor casino threads and Cloudbet thread is very often in the top and actively discussed.
People post in these thread without any paying because it is in the top.