If you don't have a heart that can be touched with this kind of reasoning, Dude, let's go with a purely selfish motive. I assume that is your wife in the pic. Or, at least someone you care about. Am I right?
Suppose, someday, she is in a dangerous situation of some kind... Oh, to keep it neutral, say a dog attack... And the only person nearby is this fellow. Would you want him to have a favorable perception of Black people, and fight the dog off... OR would you prefer for him to remember how you cost him his job (if that happens) over a remark about Black people, and to just turn his back and walk away?
This is not meant to hurt you.
This is merely the real future we each may have before us if all we ever do is escalate this nastiness of racial hatred.