"But credit reports also reflect X, Y, or Z. It's not fair to judge applicants based on that!"
And so does practically everything else that businesses use to make hiring decisions! A college degree, for instance, is hardly a perfect signal of your work ability. Among other things, it can indicate:
- Family wealth.
- Whether you were lucky enough to live in a state with affordable, high-quality public universities.
- Your sense of responsibility as a 20-year-old.
This is true even when a college degree isn't directly relevant. Most jobs that nominally require college education don't really demand anything beyond basic reading and analytical ability, and middle-school math (if that). We still accept that higher education will matter in hiring.
In a few particularly egregious circumstances, we acknowledge that some form of discrimination in hiring is so odious and societally destructive that it cannot be allowed—for instance, discrimination on the basis of race or gender. Forgive me if I don't think that credit score discrimination is clearly deserving of the same treatment. And if you think that it is, you have to explain why your argument doesn't extend to education, or work history, or the countless other imperfect and often unfair proxies that employers use to judge the suitability of job candidates.