Bunyip
pro scapegoat
I would presume honesty in cases where the person shows some familiarity with the aspect of science they are challenging and discount honesty where they do not. The 'Gish Gallop' is another great indicator - when a person simply introduces new claims, rather than defending prior claims.Aye, there was clearly dishonesty in some in that movement.
They dun got caught in the act.
But regarding posters holding unscientific beliefs, I'll presume honesty until there's evidence to the contrary.
An honest person will back a claim they make and respond to data. A dishonest person fires claims like a gattling gun in the hope one will hit.