how do the "bad guys" threaten the humanity of the prtagonists?

The fear inflicted by the "bad guys" leads many to commit suicide and most to wish they had.

"The man and the boy consider themselves good guys, which they tend to see as seeking survival without harming others. They only scavenge for food and supplies, but they try not to steal from others, and they punish those who steal from them. In contrast, the "bad guys" are willing to hurt, use, or murder others for their own benefit. Yet, a central conflict in the novel is between the boy’s idea of what good guys do, on the one hand, and what the father does, on the other hand, in being so afraid of others that he refuses to help them, and in more severely punishing others than the boy thinks is necessary."