You can’t meet that kind of argument logically. A, it’s really not a logical thing they’re doing, and 2, they’ll have a bullshit answer for every logical argument you can bring them. If confronted with something they can’t refute it simply must be a hoax. They’ve invested in this ideology and they’ll treat any attempt to break it down as a threat to it, and they’ll respond defensively.

Instead a better approach is to ask probing questions. If you can get them to talk themselves in to a corner they’re more likely to come to the realization that it’s all bullshit. Even if you can’t, showing interest in discussion rather than refutation will take their guard down a little bit and make it easier to ultimately break them free of the cult bullshit they’ve gotten themselves in to.

Deprogram, don’t fight.