Mental illness is the broad, simple answer. I don’t know enough about her to even guess at the specifics. But, people behave irrationally, poorly, meanly when they feel insecure, unsafe. Like most conservatives, she’s probably plagued by many insecurities that make her seek out something to blame and some group in which to take refuge.
Not trying to diagnose but, she could be bipolar and these at the symptoms of her swinging between the extremes.