Is there any rational explanation behind the fact that a Bitcoin forum -I repeat, a Bitcoin forum- is full of casino signatures?
This question will be more appropriate if you ask to the developers or teams of Casino sites.
Logically, if there are many casinos signatures, it means it is an effective way to promote the campaigns in this forum. I can understand it since many forum members join the gambling activities, many of them are true gamblers.
I don't really mind the fact that casinos are advertised. Or perhaps I do, because I hate gambling, but this is a personal opinion and of course, I can understand that any company wants to gather more customers.
I can understand if you seem not happy to see many casino signature campaigns because you hate gambling. Basically, this is more like your subjective assumption, you expect to see bigger number of non casino campaigns. However, this forum is free space, it is not designed to support certain projects to held their promotion.
However, my point is, is Bitcoin development so difficult? Is it a thing from the past? Nobody writes bitcoin-related software anymore? Why on earth isn't there any good bitcoin-related product advertised in the forum?
What does bitcoin-related software have to do with campaigns? Anyway, if you find out too few advertisement of bitcoin-related products, they may view the forum isn't the best place to promote their products anymore. Or they focus on social media (telegram, twitter, facebook, etc) to promote their products nowadays. We can't blame the developers, they should try varied ways in promotion. I suggest you hold a survey if you want to get valid answers. You can make a survey addressed to the developers of bitcoin-related products.