Answer:
Derrick A Bell is likely explaining the following rationale:
As you educate yourself, you get to know many other realities, from social realities to economic realities, to political realities. This increased knowledge makes you more informed and critical, in other words, makes you more enlightened.
Because of this knowlege of other realities, you also become more empathetic, because you acquire the capacity to put yourself in other people's situations. And finally, empathy naturally leads to desires to reform the negative policies that negatively affect the people you are empathizing with.