Cyber-bullying, and other issues related to violence being committed online in prosocial environments, are beginning to constitute an emergency worldwide. Institutions are particularly sensitive to the problem especially as far as teenagers are concerned inasmuch as, in cases of inter-teen episodes, the deterrent power of ordinary justice is not as effective as it is between adults. In order to develop the most suitable policies, institution should not be satisfied with statistics and sociological perspectives on the phenomenon, but rather seek a deep ethical understanding—also referring to the biological and evolutionary past of human beings. The aim of this paper is to show a way to fill this theoretical gap, offering some answers that can illuminate future policy-oriented research and reflection. In order to do so, we will start by connecting our argument to evolutionary studies carried out in the past two decades, focusing on gossip as a tool for social assortment, thus endowed with a dual function: protect the group from free riders, intruders and bullies but also bully the deviant members. In the “Mediating gossip through social networks” section, we will see which aspects of gossip, vital for bullying, are co-opted by social network scenarios. A fundamental trait of human social life, that is the subdivision in smaller coalitions, or sub-groups, will be shown as missing in social networks dynamics—therefore constituting themselves as structurally violent. The “Why and how do social networks empower bullying?” section will deal with techno-ethical and epistemological concerns regarding how gossip, mediated by SN, manages to empower cyber-bullying. The “Self-gossip and self-mobbing in the light of the disruption of sub-moralities” section will characterize cyber-bullying as often sparked by self-gossip in a scenario where familiar sub-groups, which also mediate defense and mutual understanding, are disrupted. The “Discussion and conclusion” section will consist of a philosophical summary, divided in two parts: a pars destruens analyzing whether SN, in their actual configurations, are fit for being used by humans-like-us, and a pars construens examining the broad potential consequences of highly enforced regulation aimed at contrasting cyber-bullying.