Be active, not passive. Interrupt racism as soon as you hear it. Even if it doesn’t offend you, if it offends your black friend, just say something to the other person that makes them uncomfortable and makes them think.
If my view cannot represent their reality, how the hell am I supposed to know if they're offended?
Don't you understand? That is the beauty of it. If you can forever live in fear of offending them for any, unknown reason, you will be eternally under their control.
You will give them stuff and vote how they want. You will be their slave who will be allowed to live as a dhimmi as long as it is within their ever changing prescribed bounds.