If the mainstream should always include extremists in the conversation — if gatekeeping is useless and counterproductive — then all you have to do in order to force extremist ideas into mainstream discourse is to grab some attention. If you get a Twitch stream or a podcast and you start screaming that the Holocaust was fake, or that the USSR was good, etc., and you manage to get a decently big audience by doing this, you should now have a say in how the country is run.
6mo ago