Reading the article finding a motive is difficult. She could of just decided "I'm black because profit" one day. On the other hand..she has this adopted brother who is black, and apparently abusive parents. I don't know,maybe she was abused and found solace with her black bro to the point she convinced herself she is black? I think she knows she isn't black, but still in her mind perhaps "identifies" with them more? Or it could just be a scam.
On the other hand I probably would of stopped the scam once people started hanging nooses on my house. I did chuckle at her "I've been to Mississippi, I know what a noose means!" line. Could she maybe not of guessed what a noose being put on a supposed black persons house would mean without ever having been to that state.
My only other issue is that you had some saying "transracial" can't be a thing because a black person can't just say "I'm white" and be taken as white. To be fair, this woman isn't just saying "I'm black". She took some steps to somewhat alter herself. I could right now say I'm black and people would believe me about as much as if I said I'm from Krypton.