Exactly. You can't just simply assume that job performance is statistically independent of various seemingly unrelated traits. If you suspect age discrimination, you also can't just assume that age is uncorrelated with performance. Or being short sighted, or even things like weight or height. They may be uncorrelated, or they may be correlated.
Fun fact: You can almost always score at least $10-20k if you're fired from a job if you try hard enough.
I've been on the employer side of this... you fire someone who's performing badly, and then they come back 4 months later and sue the company for [insert made up thing here].
In our case, an ex-employee is suing us for not accommodating an anxiety and migraine disability, which they never disclosed and never requested accommodations for. So now we face a discrimination lawsuit (from a non-minority) based completely on falsehoods and things that never happened.
The reason people do this is because it works! Employers will almost always settle before it goes in front of a judge in order to avoid the hassle and cost of defending the claim.
It works, but court cases are public record. Good luck getting anyone to touch you with a ten foot pole afterwards, not like the candidate can prove why they weren't selected.
Lol in my state I can see every (unsealed) civil case with a simple online query. My landlords have pretty much all done it, I don't know if the background checks show it but it's an extra 15 seconds to hedge a 10k+ potential liability.
Job performance as measured, yes, it already accounts for all biases/traits, including age, appearance, personality, performance, race and all other known/unknown biases that the people measuring the performance have.
