I say it's wrong in both senses. Factually wrong is reason enough that it should be commented on. That it's also harmful just increases the urgency. Even the non-harmful beliefs can inspire harm because actions based on them will be wrong.
"If all mankind minus one, were of one opinion, and only one person were of the contrary opinion, mankind would be no more justified in silencing that one person, than he, if he had the power, would be justified in silencing mankind."
~John Stuart Mill~
I say it's wrong in both senses. Factually wrong is reason enough that it should be commented on. That it's also harmful just increases the urgency. Even the non-harmful beliefs can inspire harm because actions based on them will be wrong.
"If all mankind minus one, were of one opinion, and only one person were of the contrary opinion, mankind would be no more justified in silencing that one person, than he, if he had the power, would be justified in silencing mankind."
~John Stuart Mill~