A common argument in philosophy is that bad ideas should occur in the open - where everyone may ridicule them. When they are cast to the shadows they can grow, under everyone's noses, in private where only there are they allowed to exist. In private, these bad ideas cannot be challenged by others and people will be convinced to believe in them, with nobody challenging the idea as a genuinely terrible idea. It gives b…
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.