Arrogance is a form of prejudice.
Calling people racist who use the word negro in reference to black people is prejudice on the part of the one claiming prejudice.
Calling blacks negroes may be outdated, but it’s not racist. You might as well say that calling someone caucasian is racist.
Blacks will agree that negro is racist, but that calling someone caucasian is not racist. That ship sails both ways.
Harboring and espousing a double standard regarding race is racist, thus arrogant.