I mean like if someone is of a different color than you and you call them using their color as a reference then it will depend on what the context is and how sensitive the person is. You yourself mught say it in an offensive way or they might take an offence to it while you didn't really mean it. So yeah these things depends on context and people in the consideration. But why use the terms, It's internet someone will always get offended if there exists a chance to offend someone.