I don't think that's true. If there is a sufficiently large group of willing listeners (or determined trolls), then having a bad idea out there in reach of tha

I don't think that's true. If there is a sufficiently large group of willing listeners (or determined trolls), then having a bad idea out there in reach of that audience legitimizes it far faster than private discussion could. At which point, challenging them invites the creation of a cult rather than dispersing the idea. For a frivolous example, my roommate is now convinced that the Star Wars prequels are legitimately good movies because of r/PrequelMemes.