In fact, the degeneration of a difference in convictions into hatred and fight ordinarily occurs only when there were essential, original similarities between the parties. The (sociologically very significant) "respect for the enemy" is usually absent where the hostility has arisen on the basis of previous solidarity. And where enough similarities continue to make confusions and blurred borderlines possible, points of difference need an emphasis not justified by the issue but only by that danger of confusion.

QUESTION: This intriguing counterintuitive idea — that hatred intensifies with proximity and shared roots rather than distance — is worth chasing further.

Georg Simmel, on individuality and social…, loc. 320