She's a narcissist

She's self-isolating because of her fame (probably was an introvert before becoming famous, as well). She was abused as a child for not being a boy by her father. She's been sexually assaulted. Then the "gender criticals" used those access points to wrench open her brain and fill her with fear. That fear made her question, and when she finally did so openly, she was met with intense anger. That drove her further into the gender critical community, where she then doubled down. The rest is history.

She became hateful the way everyone does... by thinking her hate made her a savior to those who were voiceless. It didn't, though. Just made her horrible.