> but is it a question whose answer matters

Yes. 100%. And the fact that you're not seeing why it does is confounding to me.

This person has shown that they are willing to harm society (for their own benefit, presumably); by active choice. And, as such, anything they say needs to be viewed through the lens of "is this person lying for their own benefit".

1. Their previous actions do mean that we should not trust what they are saying outright, we should do (more) work verifying the information they provide.

2. Their previous actions to _not_ mean we should avoid holding other accountable when the information provided turns out to be true.

You're asking your question like someone is arguing that this person's information doesn't matter (2); but the point being made is that we should (1).