Your whole position assumes that the other person has some kernel of truth to what they're saying. A flat Earth assumption can be right in some circumstances, but the "VACCINES CAUSE AUTISM" assumption is just insanity. It's wrong, and if your epistemology won't let you say it's wrong, your epistemology is broken, not vaccines.
> Your whole position assumes that the other person has some kernel of truth to what they're saying.
Exactly. They might have been fed garbage propositions that explain their garbage conclusions, but calling them insane, crazy, <pick-your-favorite-slur> is just a cop out of discomfort of the dialogue and co-existence, through the way of sub-humanizing them.
> It's wrong, and if your epistemology won't let you say it's wrong, your epistemology is broken, not vaccines.
I’d say on the contrary, “epistemologies” that demand purity and certainty (ideology is a better term for this) don’t tend to explain reality well and because of that they don’t survive in the long run. They are inherently maladaptive.