Only a fool trusts sentient cosmic powers, no matter what kind. I have distrusted the light for a very long time and came to the conclusion it was rotten the moment Velen and his army of the light stuff popped up back in BC. More and more evidence popped up over the years, showing the true nature of the light, I don't believe the void but the combination of both the lights clearly tyrannical actions, coupled with we learned recently and the lightforged constantly going on about the one true path, the maghar scenario and the general shady nature of the naaru.
I see literally no reason to see the light as a source worthy of any kind of devotion, only as a resource.
I don't believe, even for a second, that Lothraxion changed his mind willingly.