This is due to high biases of the judges towards black people along with lack of empathy for the black people.
Explanation:
Racial codes make it impossible for Tom to win trial because white people were extremely racist back then and even the judges were biased in favor of white people. In the book, this is demonstrated by Tom losing the trial with no factual evidence against him. Lastly, even a black person showing their feeling of pity or remorse for a white person angered white people back then because they felt they were being looked down upon.
