Some pretty scarey responses.
Here's how our legal system is supposed to work. You elect representatives. They vote to pass, change, or eliminate laws. Before the case goes to the jury, both sides (the prosecution and the defense) present proposed jury instructions (essentially telling the jury what the law is). Each side argues why a particular instruction should be given or not given based on the law. The judge decides which jury instructions comport with the law and which ones do not. All of this argument and the judge's decision is recorded/reported. If the judge decides incorrectly, the case gets appealed and the decision is overturned by a higher court.
It is not the job of the jury to disregard laws even if they don't agree with them. If you don't like a law, there are other ways to eliminate them or have them changed. One way is to elect someone who will change the law, another way is to put initiatives on the ballot to change/eliminate laws, and finally you can support organizations, like the NRA, that will help to change laws.
But to disregard the law after you took an oath to obey the law as instucted by the court is contrary to our legal system. You give your word. If your word means nothing, you should not be on a jury.
The doctrine of self defense is well established. It says in a nutshell, that if you reasonably think your life or the life of another is imminently at risk, you can take human life. The jury would be instructed accordingly. Given the limited facts that we have (probably only the facts helpful to the defense if I am understanding the thread-starter's position), it appears that defense is applicable and would allow the Defendant to escape criminal liability for killing the intruder. And rightly so, if the facts are as represented.
Felons cannot have guns. Although the law usually applies to all kinds of felons, even felonies not involving violence, we know that this felon was convicted of a violent offense. And he knows he cannot have a gun. Yet he has one. And you want to walk him on that? How insane is that?
Just like child molesters cannot be near playgrounds and schools. They know that. And if they violate that provision of their release, you want to walk them too?
We are all adults. The criminal justice system has a VERY high burden of proof. For this guy to have been convicted of a violent offense, twelve (typicall) jurors decided, beyond a reasonable doubt, that he did it. And now the consequence is that he cannot have a gun. But he doesn't care much about obeying the law. He has proven that. And now he is breaking the law again. And you want to walk him?
I am all for having guns. But I am not a violent felon. And that's the difference. Keep guns away from violent offenders and preserve the right of law-abiding citizens to protect themselves with firearms from those violent felons. Not the other way around.
