Usually people just need an eye-opener to jump out of the just world fallacy. But some people really cling to it, the way they cling to their original viewpoint in every argument. The person could have experienced the progression of a manager through their company who got started there because he was friends with so and so or went to the same prep school, and because of his personality traits continues to get promoted even though his record is subpar. They may have even complained about it in another thread. Yet, when it comes to race, they assume that this perfect meritocracy is open to everyone.