So what happens in the face of ambiguity?
Alice and Bob are locked away in a room with no observers and flip a coin. Both emerge and Alice states it came up Heads, Bob that it came up Tails.
Of course both cannot be right but there is no further information. The proper thing for a market to do would be to hover at 50/50. But would it actually do that? I suspect not, I suspect that biases in observers (perhaps the name "Alice" is culturally perceived as more trustworthy) would create a wedge and as people see that disparity developing it becomes a race to the bottom much to Bob's dismay.
But even that is the simple case where there is no history and both Alice and Bob are just arbitrary individuals nobody knows anything about beyond their name. Life is not like that. Bob being determined a liar once becomes an input to any future fraud predictions. Are people really running through proper Bayesian analysis? Again, gut feel is that the almost never do. So now you become a self-reinforcing system in a potentially really nasty way.
And even that is a relatively simple case where all inputs are ones in the market already. What if Bob has an arrest for shoplifting when he was 18 published in a local paper? What if he's been a target of one of those shady companies that publishes (real or fake) arrest records and extorts you for takedown money?
It's worth considering the possibility that the sort of dynamics reinforced by a market would be far worse than the ones available without one. At the very least you would want to experimentally test exactly what sort of effects of this nature you might expect.
Not a psychologist or even an academic here, but I'll point out that the effects that you describe on the whistelblower are exactly the same as when actively trying to break up echo chambers. There are some real parallels here. Echo chambers are like "environmental liars", not purposeful, but they put (presumably) incorrect notions in peoples' heads which is something that none of us deal well with.
Over the last eight years I made a project for myself to interject contrary opinions (which I could back up) into conversations that I felt were turning this way among friends, family, and online communities. I've felt very similar backlash to what you describe and its affected me in similar ways. I am now very loathe to push back it on all subjects except for ones where I feel I am a true expert. It simply takes far too much emotional payment.
If you're going to look for research, maybe that's a direction to look as well? Could well be two sides of the same coin.