Reason why Luhan is not so much hated by EXO is, he actually never said or showed bad blood with the group. He once shaded SM, but he actually don't talk about EXO but sometimes post stuff like him still wearing the HunHan bracelet or ring, he even cheered them at an award show when they won (and they weren't there) and Exo cheered for him when he was nominated/win in that QQ Music Awards when they attended and performed, Luhan wasn't present that night.
I feel like they actually don't hate each others and I'm sure they are still talking just not publicly to avoid SM's backlash.