A credit score is not racist because racism implies intent, however credit scores do disproportionately discriminate based on race and thus should not be used for hiring.

Consider the fact that to access any form of credit, and thus a credit score requires a bank account. When you consider the racial disparities between those who are un-banked or under banked it's clear that a credit score disproportionately affects certain communities.

Not only that, but credit ratings in general can be incredibly flawed. Many institutions had their bonds downgraded by the large credit rating agencies after the financial crisis simply due to the fact that balanced sheets were scrutinized more closely due to all the public outrage.