Who set fire to the cabin & barred the front door?
Seems likely as he watched the anointing of Natalie while holding a box of matches & doubtless realized they were descending into a self-consuming cult of wilderness worshipers.
Were that the case I think he would have invited them, right? No. I think he wanted to kill them, why else set fire when they're mostly all sleeping? Perhaps he was guided by the woman/spirit Javi alluded to after his return.
The series opening scene suggested the girls broke up into different sects. Why else would pit girl not know where the trap was? In order for them to separate like that they'd need not to live together in one location, so I see why it was necessary to destroy the cabin.
In general, I feel like they've set up a lot of interesting elements and ideas but they have no idea how to resolve them in a satisfying way. I really think they're going to drop a lot of balls before the series is out.
You might be right. I think something similar, only to a greater extent, is happening with From. It opens with a fascinating concept or series of concepts, but it seems likely the writers have become more than a bit lost.