Well I think this is blown out of proportion, personally. Actual racism is stupid and unfair, and that remark is just lower than stupid...but the guy may not even really be a racist, just some drunk idiot, and what is this world coming to when Nadolo, a Super Rugby star, responds to a tweet from some probably suburb low-life piece of crap nobody ?? - with such words as "hurtful" and a lamenting tone, "after all I've done for this club" ?
The sheep-people have always bashed celebs and pro athletes, it's just that before it was only verbal and fugitive, hot air, now it's tainted solid in permanent virtual ink online for everybody to read, and the vicinity with the targeted celeb has never been this great. I understand it hurts but guys, hey, you're pro athletes, you're stars now. The herd mentality and disgusting mediocrity of the common people sure ain't new things, they're prehistoric; and you know it's always, always, always going to be there, one of the few certainties in this world. So you've got no choice but to shut it off somehow, it's part of being famous today. It doesn't matter if the messages are racist, sexist, Buddhist, tourist or just flat aggressive, people are idiots, they'll gratuitously criticize EVERYTHING and ANYTHING.
If you make a mistake, they'll all remember, especially with YouTube there to make sure your actions go viral. If you're too good, you'll attract hatred. There's no way out, and you can't start fighting off every single fly that comes your way, or you'll spend your whole lifetime making your life tidy.