Agreed. He performed an execution after they were incapacitated, (different ballgame) This doesn’t mean you still shouldn’t be able to shoot an unarmed intruder.
The only part of this case I don’t agree with is the concept of premeditated murder. I don’t care if he hid his car, he still has a right to hang out in his own house and the two teenagers only got shot because they broke in. Finishing them off when they were down and not immediately calling authorities was his crime. Considering the man’s history as a crime victim I consider that a crime in the heat of the moment, but not premeditation.