A couple things.
'Coming before' and 'coming after', when Bakker uses those terms, do not (generally) refer to chronological order, but to causality.
So, the No-God being "the darkness that comes before the Gods" doesn't really make sense unless you are claiming that the No-God is the Gods' subconscious. Which I don't think you were.
Also, 'intentionality', when Bakker uses that word, usually refers not to the desire to act, but to the philosophical quality that an act requires as a prerequisite for meaning.
So, "sin depends on intentionality" doesn't mean that you have to deliberately intend to do evil for your actions to be sinful. It just means your actions must have meaning.
Shutting the World off from the Outside strips all acts of intentionality and so makes sin and judgement impossible. Everything becomes merely objective facts, shorn of subjective interpretations. Killing is just killing, not murder. Fucking is just fucking, not rape. Eating a man's flesh is just eating, not cannibalism. And so on.