He discarded her in the cruelest of ways, that nearly killed her.... Just with that, her coldness would be reasonable and valid.
But then he continued to stalk and harass her... Again all VALID reasons to be cold towards him.
But isn't his actions are all under the influence of the dark thing?
I don’t know how far along you are… But he wasn’t under influence…. He chose it himself
Technically initially he was caught by the demonic energy of the OGFL, but how strong said energy was when he made those initial decisions is debatable. Also, while this definitely gives context it doesn't absolve him of his actions.
The latter continued harassment was full on his decision.
I know what he did was bad but after all that why they are so cold towards him