I don't know how it works in the US but in the UK you can't just fire someone so easily you have to have written warnings, disaplinary hearings, final warnings etc. So unless you have done anything very wrong (gross misconduct) you cannot just be fired and especially not for reporting someone that is unfair dismissal even without the back story
Take the complaint up with those higher this can not be left as is they need to know if they don't do anything then take it legal
I think it depends on the workplace but racial slurs are usually taken very seriously here and people can be fired on the spot for discrimination like that.