> so the applications will often use other data points, like zip code, that end up having a correlation to bad credit as well as race. ...often producing the same result.

You realize this too is illegal right? The law doesn't say "you can't use race" - instead it says (paraphrased by the Brookings Institute): "Are people within a protected class being clearly treated differently than those of nonprotected classes, even after accounting for credit risk factors?"[1]

O'Neil points out that math is often used to obfuscate this (whether it be deliberately or not). This is a valid point, and one that people who think of math as a values neutral tool should consider.

I didn't love the book, but it's difficult to make the argument that she is stupid.

[1] https://www.brookings.edu/research/credit-denial-in-the-age-...