In any case, only you can decide when his comments are seriously impairing his job as college professor.
The thing is it's hard to know when a man like this is being fair in his marking of pupils work. For all we know his attitudes could result in his being harsh in his grades towards the work of someone from a different racial group as his. That harshness *could* cost someone a qualification.
Personally I would go take it up with a friendly black teacher and ask for advice before making an official complaint.