HUD has a rule that tenants applying for federally subsidized housing may not be denied for lack of a credit history. But for private rental arrangements federal law only requires that landlords covered by federal civil rights laws not discriminate based on factors like race, sex, religion, etc. You may want to ask a local attorney or local organization that helps renters with landlord issues what the law in your state requires.
Thanks. I did find the TN legal aid and will attempt to contact them what to do. It seems like that manager is using this to turn me away since I last voluntarily removed myself from the wait-list I was on since 2019.