To me "I don't know" is pretty close to "didn't happen" anyway. I mean we will even say "hmm, I don't know about that" to indicate skepticism.
I suppose you are picturing someone who is obstinately refusing to believe or even investigate a claim, but when I hear "null hypothesis" it's really just "you haven't given me any reason to believe this." And that's not quite the same as "I don't know" but it's not that far off either, is it? Maybe it's just me.
I don't know where you're getting this idea that I'm shutting down their experience in the way you describe. But like, do you think this story of theirs is that unique? Have you really never heard anything like this before? Because it kind of seems like it. So it's not that I'm dismissing their story out of hand, but rather stories like this are not that uncommon and generally in my experience you don't need to resort to the supernatural to explain them. So that's where I'm coming from and, again, I'm not even telling them they're wrong as you suggest, but I am reverting to the "null hypotheses" as you say. But, as I already explained, to me that's more of a "you haven't given me any reason to believe this" than it is a "you're wrong, didn't happen." Unfortunately you seem committed to taking equal offense to both, as though they are equal, and we are at an impasse.
Uh, sure they can: he saw an opportunity where he could make a difference and bring a program to light where the NSA was otherwise blatantly lying to Congress and the American people, and he took it.
There is nothing he can or could do to stop the invasion of Ukraine.
Which is to say, he didn't merely oppose US crimes. He brought them to light. Everyone already knows about Ukraine.