> it is labelled as editorial guidelines and not an editorial article
Editorial Policies
As part of the Nature Portfolio, the Nature Research journals follow common policies as detailed in the Nature Portfolio journals’ authors and referees policy pages, and we request that our authors and referees abide by all of them. Nature Portfolio journals take publication conduct seriously. We reserve the right to decline publication of a paper even after it has been accepted if it becomes apparent that there are serious problems with the scientific content or violations of our publishing policies. Particularly, we want to draw your attention to the following policies and guidelines.
I'd say they're very clear on what these are and what the consequences of violating these guidelines are. They assume their readers and potential authors understand what they mean as well. I think they are correct in their assumption that those who are interested in this publication understand both the meaning as well as the reach of these guidelines.
It is also clear from these guidelines that the City Journal article as well as the self-described neophyte (your words) were right when they said research into these areas is shunned no matter the validity of such research, that as far as this publication is concerned this is 'forbidden territory'.
> ...didn't understand the risks for harm created by his research, that's his fault and not that of the PhD programs.
No, that is an incorrect characterisation of the circumstances. There is no harm created by this research per se, what harm there might be is in the eyes of the editors of NHB in that this research enters a territory that they deem to be off-limits because it might produce outcomes that undermine the basic tenets of their world view. In reality this research and any outcomes it produces can be used both for good as well as for bad purposes just like nearly all research. The editors at NHB would rather not have to contend with research which undermines their basic tenets of all humans being identical - the 'tabula rasa' or '0% nature, 100% nurture' - so they want to keep it out of their publication (which in itself is their right although it undermines their credibility) as well as out of academic discourse (which is where they are wrong).