What happens when the lone voice is in the right, and the mass of people are in the wrong, and all of the preponderance of current science and wisdom is against the lone voice? It's no great stretch to find examples through history of this in different social contexts.
If the preponderance of current science is against the lone voice, then it's highly likely that the lone voice is not in the right.
The important bit - to me, at least - is we don't run a witch hunt against the lone voices. If they are right, they should be heard out - if they are wrong, they can ignored. And, if dangerous, they can be no-platformed, etc.