cognitive dissident
A person for whom exposure to cognitive dissonance has resulted in rational conclusions contrary to the 'official' narrative of history and/or culture. If this dissonance becomes great enough, the person will be compelled to start producing new cognitive dissonance, becoming a cognitive dissident.
Example:
An activist who disseminates information aimed at changing peoples opinions regarding an immoral status-quo could be regarded as a cognitive dissident
An activist who disseminates information aimed at changing peoples opinions regarding an immoral status-quo could be regarded as a cognitive dissident