Dictionary result for the word "negro":
Negro Definition | Definition of Negro at Dictionary.com
IMO, I don't think the word negro is considered bad or offensive. Though, times have changed, it would not be appropriate to use in our language. I don't see why, but it just is. I guess it is a word that has "gone out of style" or the Civil Rights Movement has affected the meaning of "negro". But I do recall Dr.MLK jr. referring to black people as negros.
The word nigger, I think is a rude slang of the word negro that is highly inappropriate
because it is used in a manner of bad language.
I don't understand why saying nigger today to a friend, in media, or just to be insulting is not as big of a deal. But if you hear somebody say negro, it's just WEIRD compared to saying nigger.
What I find annoying today is when somebody is called an African American. You're an
AMERICAN if you were born in America. You may have an African
background, but you're not quite literally from Africa.