A discussion can be useful only if all the parties to it can say--sincerely: "But I could be wrong." When that is not the case, you have a religious argument.
Religious arguments are not necessarily about religion. An example: Yankees vs. Red Sox. Not much actual religion there, but still: people's minds are made up, and they are not to be swayed by "facts" or "reasoning" or "experience."
Humans are the only animals that can contemplate their own demise. It's natural for humans to want to control their environment: to prevent early death, if possible; if not, at least to predict it; or, failing even that, to be able to explain it with "if only." "If only we had known what 'they' know, this wouldn't have been such a surprise."
In olden times, people invented "god(s)" to provide such explanations. New deities of disaster are a tough sell nowadays, so instead people invent conspiracies. The motivation, whether buying into gods or into a conspiracy, is precisely the same: "'They' kept it secret from us--otherwise we'd have prevented this terrible thing, or at least been able to see it coming."
Bad stuff happens. It can't all be prevented; it can't all be foreseen; some of it, we can't even genuinely explain. But that feels terrible, so we create a conspiracy (or a deity) to soothe ourselves: "Of course we didn't see it coming; they made sure of that!" Here's the irony:
By inventing conspiracies (or deities) to make ourselves feel better--making up our minds, regardless of evidence or logic--we make it less likely that we'll prevent or foresee the next disaster.