I Don't think the "White Boy" Comments make any difference to Calzaghe, I Think the real reason Calzaghe wont rematch Hopkins is because despite Calzaghe winning the fight, Hopkins made him look like **** as he does to most of his opponents. Calzaghe was very disappointed with his performance as he should be and i don't think he'll want to go down that road again.
Regardless of how you saw the fight or what you feel about a rematch, the white boy comment was pure pre-fight hype (remember the Puerto Rican flag) and in no way indicative of racism on Hopkins' part. You could question the judgment of the remark ( I wouldn't) or the respect of stomping on a flag, but things like that happen all the time to build up a fight. I doubt very much if the Joe gave a **** about the comment, one way or another.