The Bolito as a Token of Progress
The Counselor paints a bleak view of modernity and human relations. Everyone is an object, "replicable, replaceable, disposable," and this interpersonal distinction is highlighted rather clearly with the bolito. The bolito is a depersonalized weapon of destruction, making it the ultimate tool for death in the modern landscape. It requires no mastery or training, and its hyper-violent execution stands in contrast to, say, Anton Chigurh's captive bolt stunner, which is a tool meant to kill with a minimal level of suffering.
The bolito is symbolic of the unstoppable and indestructible force of modernity, and a testimonial to the decaying nature of the interhuman relationship. Its mechanized element removes the user from a sense of agency previously the domain of the individual (i.e., conventional weapons) and negates moral choice. There is an attenuated sense of accountability in its use, leaving no trace of its perpetrator, and bulwarking notions of modern digital anonymity.
Beyond the veneer of progress, one can view the bolito as a symbol of depravity and social inadequacy, shining a light on the grimmer side of technological innovation.