I didn’t read it that way. I agree to a point, that we can accept solemnly accept that sometimes bad guys need to be killed, without glorifying the deed. In my adult life, I’ve come to support the death penalty, but I don’t find any joy in an execution. If anything, I feel the deepest sympathy for those who had to carry it out.
The author mainly was pointing out(after a few chosen sob story sentences)that this situation could have been handled differently, which means he thinks the perp shouldn't have been killed. First of all he has no way of knowing what really happened and whether violence was the only way out or not. Secondly, anyone, and I mean ANYONE, who breaks into someone's house with intent to steal, rob, maim or kill(any or all of the previous)deserves whatever happens to them. The home owner should feel no guilt, he didn't ask for the situation, it was thrust upon him and if a person has never been in that situation they have no right to judge someone who has been and who has killed what could have been their killer if they had hesitated.
BTW, the victim(the real victim)did retreat at first but the guy followed him, too bad for the perp.