I have told this behaviour to the bookie to which these spam webs redirect. They told me they would speak to the spam affiliate. They have spoken and the spam affiliate no longer redirects to the bookie, but to a webpage with the banner itself. That is: hidden spam. I imagine that the spam affiliate is powerful and that is why they have not been fired.
I have to say that since I reported this behaviour to the bookie, the posts in my blog do not get indexed by google anymore. I suppose that the spam affiliate has taken
SEO action against me.