Currently, differences in worldviews, especially those of ideological and political nature, are promoting a climate of polarization, whether in the offline or online environment. One of the ammunitions used in the we versus they war is knowledge. Heated discussions are supported by a dispute of right or wrong, that is, who is right in defending a determined position. In the light of an approach that integrates the theory of knowledge to the studies on epistemic stance, from the perspective of the Conversation Analysis, this paper aims to examine how epistemic changes are constructed in the comments section of a digital newspaper, hosted on YouTube, which posts videos of police operations evaluated as abusive. The results demonstrate that the participants seek to defeat the opponent by invoking an epistemic imbalance between the parties. To this end, they mobilize different linguistic resources to claim an epistemic stance of more knowledge and delegitimize positions that are not supported by reliable and well-founded knowledge. The results also reveal that, in terms of argumentative effects, epistemic battles are a game with no winners. They do not contribute to modifying misleading beliefs, false information, and prejudices. They only serve to reinforce the construction of totalizing identities, hindering any possibility of mutual understanding, even if there is no agreement.