Key bit here: > Devoid of any information about the candidates’ actual qualifications, the hiring managers judged the candidates from higher social classes as more likely to be competent for the job, and a better fit for it than the applicants from lower social classes. Moreover, they assigned the applicants from higher social classes more lucrative salaries and signing bonuses than the candidates with lower social s…
I read that as them trying to control for other factors and get a clean signal to demonstrate their hypothesis as a testable, verifiable, and falsifiable phenomenon.
But some people apparently think that the process of isolation IS the confounding factor that produces the results.
This makes things difficult. If they don't do this people will accuse them of not controlling for everything but when they do do it then they say "well yeah, you're controlling for everything else, of course you'll get that".
The point from my reading was all things being equal except for the subtle verbal patterns of class, the verbal patterns are a real influencing factor in outcome