Gotta say, that is one shockingly idiotic god.
He already knows the MC will just keep reincarnating and even said himself that the memories will always return eventually. By making each life as miserable as possible, he is creating something that is un-killable, giving it overwhelming power and teaching it to hate him as much as possible.
If he was really trying to create something that will inevitably utterly end him and likely most of the other gods at the same time, he is doing an almost perfect job of it. The only flaw is that he hasn't managed to build up enough quite enough hate yet.