Well, peope tend to have their likes/dislikes regardless of what they are good at. The amount of time that guy spends training, I assure you he has practiced rg, and he is most certainly the body type/flexibility I would expect to be good at it.
Maybe he just feels he has some other things that play much better to his game, and its not so much he doesnt feel rg is any good, but just not the best for him?