Most people with mental illness are not violent and only 3-5% of violent acts can be attributed to individuals living with a serious mental illness. People with severe mental illnesses are over 10 times more likely to be victims of violent crime than the general population.
Some people with borderline personality disorder are dangerous. Most people with borderline personality disorder are not dangerous. Most violent criminals do not have BPD. But the ones who do — oh, you'll hear about those ones.