The problem with echo chambers isn't so much verification (is the information accurate?) but rather validation (is the process of acceptance rational or qualified?).

Echo chambers tend to be hyper-subjective, which means new information is accepted or rejected on the basis of content-oriented rules opposed to whether decisions upon the information are valid, qualified, or balanced. That suggests the injection of precisely targeted information focusing on group acceptance is the only criteria of success, which makes the group dangerously susceptible to manipulation.

Counter-intuitively echo chambers are primarily desirable for a number of irrational reasons not related to subject matter. People tend to find security in conforming group dynamics, generally fear originality, and strongly enjoy commitment even in opposition to strong evidence.

Contrarily, in echo chamber opposed groups the primary qualifier of information acceptance is process of argumentation. The idea or information that survives a brutal, but process-approved, argument is the most worthy. That form of objectivity can be emotionally disruptive for persons not prepared or understanding of the group process.