Kind of an "if it's only about the real world, it's off-topic; if it's about how it's tied to Dune, it's murky" situation.
Disclaimer: I'm certainly not the most knowledgeable person about Dune in these parts, but I don't think that's a problem.
I don't understand why this question was closed, at least not as "off-topic". From what I get by reading the question and (admittedly skimming) article, this is a written piece:
- by the author of a major SF work;
- talking about said work;
- in Omni (the magazine).
And the question asks about the meaning of a sentence in the context of that Dune explanation. So far, I'm not seeing anything blatantly off-topic.
If I understand that right, this is basically asking "what does Dune tell us about Herbert's statement of humans not having equal ability", which I think falls under literary analysis. Per Is literary analysis on-topic?, this is on-topic as long as it can be answered without (too much) speculation. Typically these could fall under "too broad" or "primarily opinion-based", but certainly not off-topic.
Once again I only know the very big outlines of Dune (shoot me), but for the peasant I am, it seems big enough of an universe and "behind the scenes" info for the question at stake to be answered (in a way that fits SE's format).
It might put some people off that it's been cross-posted on Politics.SE, but I'd argue that a SFF answer backed with quotes etc wouldn't be redundant with the answers there - so far there's only one undetailed mention of a character, Vlad Harkonnen.
To put it in a nutshell, I think the question is fine as is and should be reopened (and voted as such). I may be missing something though, and as I'm unsure whether the uncertainty stems from my lack of Dune knowledge, my misunderstanding of one of our policies, or something else, I'm looking forward to clarifications.