This will happen behind closed doors among smart people who, through some very old traditions of communication, can cooperatively discover the bad information. The miasma and murky ocean puzzle pieces don’t need to be fitted.
I think there is objective truth but our individual viewpoints only glance off it… so maybe it’s more correct to say, “there is no objective truth that can be known.”
I think even folks who hate, fear, are violent, got that way through some experience. Is that experience invalid? They’ve seen and experienced a world others haven’t. It’s real to them.
Is morality grounds to discount a real perspective?
In my opinion it may be enough to discount it on some matters but one false belief in a sea of a human’s opinions is not enough to discount all of their viewpoint outright.