Maybe not in your mind, but the term 'negro' is considered to be an offensive racial term by the vast majority of blacks in this country, and has been since the mid sixties.
I'm telling you this as a black man, myself. Now, if you insist upon continuing to use the term, you'll do it knowing that you're insulting every black person who sees or hears your comment.
The thing is, opinions vary. I remember using the word, “black” once around 1990 and a white woman told me, “It’s ‘afro-american’. They don’t like to be called black.” I bristled at the apparent terminology change. I remember it so clearly because that same week I saw an article regarding the new name change to african american and the fact that when blacks were polled, the overwhelming majority of them preferred “black” to “african american”.
I really don’t care. I’m a human being and I belong to a particular race. I don’t care what word people use to describe my race. Call me caucasian. Call me white. Hell, call me honky. I really don’t care.
And I treat others the same. Do unto others as you would have them do unto you. If a negro tells me he doesn’t like that name, I’ll ask him what he does prefer and that is what I’ll call him from that moment on, assuming he’s not just doing it for attention. I compare this to the gender pronoun nonsense Peterson talks about.
Words are symbols. That is all they are. Their function is to aid in communication. Everybody knows what Caucasian means, and everybody knows what Negro means. Neither is used as a derogatory word.