Final answer:
Faber encourages Montag to pity those he's trying to enlighten, recognizing their victimhood within a flawed system, and suggesting that empathy can lead to transformative revelations.
Step-by-step explanation:
Faber instructs Montag to pity the people he's trying to reach because he recognizes the complex societal issues that have led them to their current state of ignorance and conformity. It is an understanding that the people are victims of systemic problems beyond their control, and therefore, they deserve empathy rather than disdain. This approach is likely to engender a deeper connection and possibly spur a revelation that can lead to change.
From the context provided, we can infer that the importance of pity in the face of suffering is a humanizing force, one that allows us to see the struggles of others and the need for compassion even when we seek to challenge and reform the underlying issues creating the suffering.