He might have kept a journal because his therapist suggested it, but that doesn't mean the therapist ever had his journal, read it, or provided it to the authorities.

Anyway, as someone else said, unless OP is famous, or is writing specific plans to cause harm, there is really no reason for the T to do anything with OP's journal entry. Apparently he hasn't even read it. Personally I'd ask him to shred it and move on.

OP: I find myself wondering, how are you dealing with your anger that your T isn't interested in reading your journal? Are you planning on seeking therapy elsewhere after you terminate with this one?