He made a racist remark, but if he didn't intend to denigrate Desailly because of his skin colour, then he wasn't racist, no.
I think he just had a mental abberation, that's all. He didn't outright call him by the words he used, he said some people would refer to him as *insert Ron's words*.
You never truly know what is going through someone's mind. I can only go with my gut feeling that he isn't a racist, just someone who's prone to making daft unthinking comments.
That said, he had to resign. I just hope he comes back at some stage, but at 65, he probably won't.