So they approved of you seeking help, and supported that endeavor, but they deserved to be assaulted anyway?
You don't surrender yourself completely to your phobia is the BIG thing here. You can keep talking about how this phobia has won, but you'll never get over it. You don't even try to fight back. Therapy can only help you if you WANT to be helped. When you've completely given up all hope that you'll overcome this phobia then you don't want help. You just want to stew in the negativity its wrought.
You know what? I take back what I said about being worried that you'll become the next mass murderer. You're terrified, of everything. Maybe you'll lash out at your parents again, but you can't even look at your phobia and think "yeah, I can beat this thing". I doubt you can approach a stranger with an inkling of the same bravado that you wrap yourself in online.