Definition of slur

1 a : an insulting or disparaging remark or innuendo : aspersion


So stop being pedantic. It is literally the definition of a slur.
You're seeming to want to conflate it with the appropriateness of a slur, i.e. Would it be bleeped by the FCC or could someone get away with it without going through HR
But you're missing the point, it's inappropriate name calling meant to disparge another person based on racism. It's a slur.