Because from my observations, your ANN thread is not virtually friendly since there is nothing like images and other pituural materials that can easily attract and catch the attention of others.
Also the title of the ANN thread starting with "found the game with highest .." does not seem professional one. OP should see the other gambling sites' ANN thread's title and details, and try to modify it in those manner as it will create more visibility and give a more professional look.
That experience proved to me that indeed, the use of referral links in posts on this forum is highly prohibited.
As far as I know a little about referral links, we can use referral links in the signature but cannot post the referral link anywhere on the forum.
Anyway, this is a new learning for me that the owner of the ANN thread can put a referral link in the post in order to track the traffic.