Because contrary to the page, they don't really care about the spam that much. Now, if more people started calling the support for every spam they get... that would translate to some real cost.
I just don't have sympathy though - ideally people would DoS all the telco and local government lines until the issue is fixed. It's just stupid how many years this exists without obvious solutions.
I suppose that would be like spamming the carriers. Not sure that's better, but it might make them act.
Also, the more spammers reported the less to bill for the calls. As less spam calls.