This question is further confounded by the fact the perpetrator was, according to his wife, an abusive, unstable man suffering from bipolar disorder.

A more appropriate question would be: what is the role of the FBI in counter-terror operations? How were they not able to prevent this incident, despite "preventing" hundreds of high profile incidents prior to this?

Out of the 508 terrorism-related cases since September 11, 2001, more often than not, the FBI has had a hand in creating the very terrorist threat they have claimed to be protecting us from. Two-hundred and forty-three of these cases involved an FBI informant. In many instances, the targets of these operations, who are later accused of plotting attacks, are not only almost always Muslim, but they are also often suffering from a mental illness, such as schizophrenia. Moreover, the targets are also vulnerable and easily susceptible to bribery as they are desperate for money – so desperate, it seems, they will help put their own friends behind bars.