Since I know nothing about her work, it may well be that Professor De Cruz is someone who has been a victim of pernicious "prestige" bias. Pernicious prestige bias is when someone thinks that because someone got a PhD from Fancy Pants University they must be competent (or, the reverse). That's bullshit and pernicious, of course, and the PGR upset that apple cart a long time ago. But what most cyber-complainers call "prestige bias" is that hiring departments prefer candidates from well-regarded departments. That's plainly true, but perhaps well-regarded departments are so-regarded because they are actually departments with very good faculty and very goods student? Prof. De Cruz never fairly considers that possibility. Non-pernicious prestige bias is simply a rational and time-saving heuristic for identifying candidates with excellent qualifications trained by excellent faculty, attributes that, in the PGR era, are well-tracked by what's now called "prestige." As Prof. De Cruz notes, "prestige" bias is a feature of academic hiring in all disciplines; the difference in philosophy is that it no longer simply tracks "brand name" universities, but now reflects where the strongest clusters of philosophers and students actually are. (In what other academic field does everyone know that two of the very best programs are at NYU and Rutgers? There is none.)
"Excellence" doesn't, in reality, exclude any demographic groups, except the mediocre.--Brian Leiter.
Let's stipulate, for the sake of argument, that (i) "well-regarded departments are so-regarded because they are actually departments with very good faculty." Let's also stipulate (ii) "Non-pernicious prestige bias is simply a rational and time-saving heuristic for identifying candidates with excellent qualifications trained by excellent faculty." And, let's stipulate, (iii) more controversially, that the quality of (ii) "in the PGR era," is "well-tracked by what's now called "prestige"" in the PGR ecology.
So far so good. Now after (i) Brian also added (i*) "and very goods [sic] student [sic]." This is non-trivial and more controversial. It suggests that the best ranked departments are excellent at recruiting the very best students. Now, let's allow, again for the sake of argument, that the top PGR departments will get (thanks to influence of PGR) 'the best' applicant pools. But it also suggests that we are ultra-confident about relative judgments of quality as predictors of future quality when it comes to people (often in their early 20s) with BAs (and increasingly MAs); little is known about their ability to deal with adversity, to deal with rejection, what their work habits are, etc. I would love to see some data-driven evidence on how good recruitment metrics really are (beyond generic claims about GRE scores).
Anyway, my point is this: the PGR evaluators are not asked to rank departments' perceived ability in recruitment. I am not suggesting nobody has insight about this; undoubtedly graduate admissions officers at top departments have some knowledge about how at least some of their perceived competitors do. They are quite aware locally of the cascade of decisions that occur around April each year.
The reason why the nature of recruitment matters is that in obtaining Brian's favored conclusion -- (iv) "Excellence" doesn't, in reality, exclude any demographic groups, except the mediocre" -- is that recruitment, too, depends on fallible heuristics. The heuristics may well do reasonable well as advertised, but that's compatible with them not catching everybody that's worthy of being caught. (It is, in fact, not unheard of, of folk coming out of lower ranked departments going on to very distinguished careers.) This matters because it is by no means obvious that those heuristics that drive recruitment won't screen out some demographics (e.g., due to tacit biases, uni-dimensional heuristics, network effects, etc.)--given that the total number of students recruited into top PhD programs annually is fairly small demographic mishaps can occur easily (especially if they all rely on similar heuristics). The PGR is simply not designed to help explore that issue.
It is undeniable (there is sociology of science research on this) that those with access to resources and willingness of others to help do well in the competitive environment of academia. Those that benefit from prestige get access to such resources and willingness. And [perhaps this is self-serving] those that flourish all tend to merit it. But it does not follow that we can counter-factually conclude that others who do no so benefit from these resources would not have flourished supposing they would have benefited from prestige. Undoubtedly, Prof. De Cruz -- who in addition to being a prolific blogger is, just for the record, a world class scholar in several areas of specialty -- is making more points than that, but she is also making that non-trivial point. I don't see why Brian Leiter can't acknowledge it.