Objective This study illuminates the communicative and social qualities of naturally occurring public resistance to authoritative debunking of political misperceptions, rumors, and conspiracy theories. Developing the concept of a “rumor community,” it highlights aspects of rumoring processes overlooked by psychological approaches common in misperception research. Methods Over 2,000 user‐generated comments from the “vaccines cause autism” rumor community, produced as the medical study that had sparked the rumor was retracted and ultimately denounced as fraudulent, are examined for their contribution to the public conversation about vaccine safety. Results Rumor community members publicly counterargue debunking messages, which creates a communication environment offering argumentative resources to community members and reaffirming the community's solidarity. Members assert their credibility to gain authority to speak, countering science with personal experience. Highlighting their interconnection with more conventional social groups and venerable social truisms, members generate discourse that legitimates their beliefs. Conclusions The process of rumor debunking does not solely involve psychological persuasion but must also account for the social geography of rumor communities and their contributions to the communication environment.