Why is Gwyn considered the villain?

He could've wiped out all the humans instead of cursing them, he instead chose to try and find another way of resolving this conflict between light and dark.

"Oh, he should just let fire end and let the natural flow of things play out"...and let all his people perish in the proccess?

Literally all evidence we have that Gwyn is somehow evil comes from other NPCs (and nonetheless, NPCs that try to manipulate you anyways) so who cares? I always found it stupid that people just take on face value anything the NPCs say, like, they're characters INSIDE the game with their own motivations, they could very well be lying.

Maybe there's something I'm not catching yet, but none of this narrative makes sense to me, all the "darkness is good" propaganda feels like a lie the game is desperately trying to convince us.