Even if a casino wanted they cannot really afford to ignore this forum, as even if they were to become successful without it, eventually their customers will begin to post reviews about their experiences there and not every single one of them will be positive, so in order to protect their image they will have to interact with some of those gamblers in the forum and sometimes show evidence that things did not happened as they stated, and if this is going to be the case anyway then they might as well advertise here and try to sway some gamblers to play on their platform by the use of signature campaigns.
It's not really about being predictive and ignoring the forum or any place that has the potential to provide a boost to your platform, but it is more about not being aware of it. If a casino finds out about the forum for the first time through user reviews, I bet they wouldn't know how things work around but they will definitely like to utilize the forum in some way to get profits.
A casino wouldn't only join the forum to respond to a user who might have created a thread here with either positive or negative feedback, if they join, the main and actual purpose of that would obviously be to advertise themselves.