NO IM SO CURIOUS WHY HE FEAR HUMAN CONTACT

Hm... from previous chapters, I think it's related to his mom's death.
My theory is the shitty dad and bitch stepmom poisoned his mom slowly and maybe caused her dying slowly and deformed.
And usually a woman in that situation might have lost their mind...
And maybe in her last moment she grabbed Damian and told him "it's too late" and died horribly.
And Damian got PTSD from that.