The spam flag says that the question or answer "Exists only to promote a product or service, does not disclose the author's affiliation."
The question that provoked me to ask this question is the soon to be deleted question Content Marketing Services to Boost Your Business Growth!. The questioner's user ID is the questioner's website, so it definitely fails to pass the "does not disclose the author's affiliation" test. This is nonetheless blatant spam. Moreover, the "does not disclose the author's affiliation" links to the How to not be a spammer page. If I was a spammer (which I am not), I would read that page as "How to be a spammer, and get away with it".
My question: Is there a rationale for the "does not disclose the author's affiliation" clause?