Earlier quoted context omitted.
But in actual intellectual discourse, if someone presents a point of view which is founded on a discredited idea, then we just ignore them. We do not show up at their talks and try to prevent them from communicating with others. Firstly because life's too short for that, and secondly because who knows, one day they might turn out to have been right or mostly right.
Being wrong is not absolute proof that nobody will follow or agree with these wrong beliefs. Climate scientists, for example, have spent a lot of time arguing in public about the merits of climate science and the lies of deniers. That is important work because the deniers do convince some people and denialism causes real harm.
That is a tragedy not because the targets are indeed often wrong, but because it has a negative impact on when student activism is required and can have positive influences as it so often had in the past. I can be dismissed with references to incidence like those where people just were shouted down.