edit: accidentally removed the quote i was commenting on when editing in Stross' comment, here it is again:
a belief in psi powers implicitly supports an ideology of racial supremacy, and indeed, that's about the only explanation I can see for Campbell's publication of the weirder stories of A. E. Van Vogt.
Maybe it's me but I don't think that is so self evident a claim to be posited without further explanation.
Best I can come up is he means the necessary implication of having superabled people in a fictional setting is that you have a de facto racial elite, even if the concept rarely breaches the surface of the text, like in the unfortunate sequel to the Dark Knight Returns by Frank Miller.
Edit: he addresses it in the comments (can't find a way to direct link from phone, its comment #14) I wasn't far off:
If you're a glutton for punishment, (re-)read Slan by A. E. Van Vogt.
Secret superrace with super-mind powers! It's totally a meme in vintage SF (goes back at least as far as Bulwer-Lytton's The Coming Race in the 19th century) and you rapidly end up with eugenics and breeding for desired traits (eg. psi powers).
On one hand it's encouraging that the comments are mostly pushing back.
On the other hand a lot of them do so on the basis of a disagreement over the moral calculus of how many chickens a first trimester fetus should be worth, and whether that makes pushing for abortion bans inefficient compared to efforts to reduce the killing of farm animals for food.
Which, while pants-on-head bizarre in any other context, seems fairly normal by EA standards.