Indeed, dualism often necessitates the construction of many false dichotomies, and as we can see here, a metaphysical sort of dotted line that says "love stops here, hate begins here". Obviously for the two concepts to be separate they need differences, and they exist, although the line is not so clear as a dualistic perception would have it. Love and hate are hardly black and white concepts, and really the intense sense of fascination that both involve means that that each can become the other easily. One's intense sense of love for a person for example, can create an idealistic picture in the mind which is then never fulfilled in real interactions with the person, then the fascination continues but the feelings about the person become negative, one might begin to hate a person based on them not living up to love's idealistic mind-portrait. That is just to illustrate that the "energy" of the emotion, so to speak, is transferable. Now, as for measuring John's hatred for himself, I still say that self hatred would ultimately equal the urge for self destruction.