Guessing there won't be too many more break ins at the guys house now that the teens know he isn't playing around.
I believe you have the right to protect yourself but not to execute the intruder once disabled.Pretty sure that is also the intent of most American law.Executions are only to be done by the state after a fair trial.And yes I do realize criminals kill some of their victims every day.
If the homeowner or intended victim fires multiple shots at one time and kills the intruder that is one thing;but shooting the unarmed,disabled criminal lying on the floor is going too far.ONLY if the criminal is still struggling to reach a weapon does he or she still constitute a legitimate target.
Legally the threat made by anyone to kill someone else is not grounds for execution;even threatening the President is not an automatic death sentence.
YOU may feel that anyone uttering a death threat should be killed at the first chance but American law doesn’t agree with you.