That story from Brown, about the black dots moving up the hill, is a textbook wild boar observation. To the extent that hogs are known to run directly uphill when spooked. They would be in this area.
Their recordings of the "rock rain" are quite obviously squirrels feeding in the trees above the cabin. You can even hear one chuffing at the end of the clip they played on the bigfoot show.
I do generally agree with your point about their actually believing some of their claims. They whip themselves up into thinking all kinds of mundane things are bigfoot related. Fact is, none of these guys spent enough time in the woods to be able to tell the difference. Case in point, on the NAWAC page, Brown describes himself as a "naturalist". Yet on an episode of the BFS, he states that he is from LA, and went into the woods basically for the first time in the early 2000s. And that's the group's leadership.