Blimey. When I posted this thread I didn't expect a storm.
I can understand why not everyone is able to sympathize with him, because there are different types of hardships in life, and it isn't always easy to identify with them if you haven't experienced the exact same thing.
The friend of a friend of mine was left with the undesired responsibility of man of the household. Sole protector to his mother. It wasn't easy, and the pressure was often tough to deal with. To be forced to wear that mantle was very much a burden for him at times, and this friend of a friend often got angry. It was a very real anger that was difficult to control, because it was based off of deeply coiled emotions. This friend of a friend turned out pretty well in the end, and I would say that he is very good at controlling his emotions these days, but it took a while.
I'm not saying that every young man in that position would react the same way, but what I am saying is that I personally understand why JJ is the way he is. I also know that he can't help the way he reacts at times. Unpleasant at times, most definitely. Flawed. But human and, I feel, good intentioned.
My OH's dad died when OH was 14. The OH was left the eldest of three grieving kids, trying to support a grieving mum. He grew up to be kind, sensible and the least angry or confrontational person I know of.