If you have the courage to stand up against racism, as Azeem Rafiq has done, then you must know that your own record will be searched minutely. It would have been better if he had admitted sending these posts/tweets/whatever, right at the start and said that now he has had experience of racism himself, he realises just how heinous his own offence was.
Anyone can admit being deeply ashamed of themselves to get themselves out of trouble, without having to change their unexpressed views and with no apopogy to the people he has himself, subjected to racism.