The Luonnotars immunity comes from a single event. You have to understand that the people of Erebus do not have the direct access to the religion page and history that you guys do. Neither did the players in the campaigns. The gods were kept intentionally vague, and there were tons of fake gods, and gods called different names in different areas. Inside that whole mix was a group who denied that they were gods at all. this was in a world where that abounded with the active stories of gods, magic and angels. It was beyond blashemy, it was idiodic. But the blashemy was enough for the Order, and they rounded up those they could find (the Luonnotar kept their membership secret). They were chained in the city plaza and told to repent for their blashemy, to repent of their claims that the gods werent real gods. The Luonnotar refused so the Order high priest called down a pillar of fire to destroy them. The pillar scorched the stone of the plaza, burnt off the chains but left the Luonnotar unhurt. The reason they werent hurt wasnt because the One exerted any influence (he hadn't), but because Junil was unwilling to harm those that were actually correct. The gods in general are confused about the Luonnotar, and worry that their knowledge might be evidence that the One has returned to tell them the truth (since the gods didnt tell them this). So it isnt that they are immune, just that the gods have, thus far, refused to act against the Luonnotar.