Have you ever lived with someone with a mental illness? I definitely see the relationship with terrorism. Terrorism thrives on fear - "will they attack today?", "Will they use some horrible method of attack?", "Will I be able to handle it?", etc.

Living with someone with mental illness can strike fear into a person. "When I get home from work, will I get normal spouse, or lunatic spouse?", "Will I need to take my children away from this situation, or will we have a nice normal meal?", "Will I get fired for constantly having to leave work to deal with this shit, or will it calm down for long enough that I can accomplish some of my life goals?"

It can be very terrifying dealing with something like this, and frankly, I find the metaphor extremely apt. I understand your distaste of how the word is used in the media, but please understand that not all of us use these words lightly. These diseases really can be literally terrifying to the people around the disabled. It can literally feel like someone or something is torturing your loved ones when you see what happens to them.