Black people commit and are convicted of commiting significantly crime more than white people per capita. Whether this is due to racism, economics, or whatever is irrelevant, but when you can't check specifically for criminal records race becomes an excellent proxy. ~4% of white men will go to jail at some point in their life vs about 28% of black men.
https://bjs.ojp.gov/content/pub/pdf/Llgsfp.pdfThat said, sex is also an excellent proxy since men commit far more crime than women. I wonder if women are more likely to get hired when criminal background checks are forbidden?