We get it, she's a psychopath, does not feel empathy, yet maybe has fun acting and dating (black) people.
But then if she doesn't feel empathy, why does she care about her family and actually brings these black people to the house? If she could actually feel love towards any human being, she'd prefer to keep Chris alive before her family as she finds them old-school and somewhat racist (as she says to Chris).
If she enjoyed acting with Chris for 5 months (and didn't seem tired of it as you see her putting efforts in laughing with him or bringing him snacks etc), why would she just give him away?
Maybe she just likes change and would enjoy moving on to her next victim but again she didn't seem tired of playing with Chris at all.