That kind of posts happens when a signature campaign requires x amount of post in the gambling section whereas these users don't even know what gambling is, posting nonsense just for the requirements.
So if you don't know what to post in the gambling section, just don't participate in signature campaigns that requires it.
I will further add that if anyone is not involved in gambling, he should not apply in gambling related signatures because this will only add to spam. How can anyone contribute to the gambling section (other then this site is good and this is bad), when he have no knowledge about the gambling. Maybe that's another reason why gambling discussion thread is more like a trash.
Another problem is that most of the campaigns and the long lasting ones are relate to gambling. I think more than 60% of the campaigns are for the promotion of gambling sites and there is not much choice.