Its actually quite simple; if a person believes that good things happen to good people then it stands to reason that they also believe that bad things happen to bad people. Further, if they often complain that bad things happen to them then one can only deduce, as per their own belief system, that they must be bad people. If one takes this reasoning further then white people must be bad because nothing good ever seems to happen to them.

Of course one could also accept that the statement "good things happen to good people" is totally meaningless and has no value given that good things also happen to bad people, that bad things also happen to good people and then nothing actually happens most of the time...