There could be a number of explanations for these behaviors that do not rely on rational choice. Let us look at two of them.
First, we can say that drug dealers' behaviors rest on the emotional and psychological characteristics of young men. Young men seem to be inherently competitive and belligerent. Since drug dealers are typically young men in a situation where there is little in the way of controls over their behavior, they become violent and aggressive due not to rational choice but to emotions.
Second, some would argue that drug dealers tend to come out of a "culture of poverty." In this view, the culture of poor areas in the inner cities is an inherently destructive culture. People in this culture, it is argued, are not socialized to think in the long term. They want instant gratification and are not good at self-control. In this view, drug dealers' behavior can be linked to the culture in which they live.