Why shouldn’t I hate my oppressor?
Short answer: because hate won’t liberate.
Longer answer: hatred is reactionary; there is nothing creative about it; so it is easily co-opted by the system. Really the system is built on hatred; so hating the system is playing the master’s game with the master’s tools. Hatred works fine on the weak and powerless, not so well on the rich and powerful. The first and worst oppressed by hatred are the haters themselves; they crush their own spirits. Haters are rigid, paranoid, conformist and doctrinaire; they lack humor, imagination, compassion and vision; so their programs either fail outright or succeed in the worst possible way.
If a hate-based movement were to solve the problems that it claims to fight, then the people will no longer need the movement, and they will abandon it, for hatred is repulsive; but if somehow hatred makes the problem no better, or even worse, then the movement’s future existence is assured. Therefore hate-based movements have perverse incentives, and are inherently corrupt.