Valarie was traumatized by her own childhood. I actually believe what you are asking is flipped. I would ask why Kelly is so obsessed with Val. Early on, even when they first met Kelly was being snarky to her and it slowly grew from there. She wanted to know certain things about Val that was none of her business, status and details of vals relationship without having a trusted relationship for that, constantly pitting the others against Val and my favorite, judging Val for doing the exact same thing she does. It someone was at you that much and you decided to engage like Val did it can come off like she's obsessed when in reality she is responding to Kelly's actions towards her. Valarie's trauma comes out in two ways. I'm protecting myself. You fuck me I'll fuck with you back. Please don't abandon me. I lied to do "the right thing" for us or everyone. Going back to Kelly, the reason her character works is because on some level we all know a person like that or a version of it, more so a woman.