I wouldn't ever consider shooting someone with a gun under any circumstances. Unless of course they broke into my home. That experience has the potential to turn many peaceful individuals into potential murderers.
Why shoot to kill? Do you honestly want that guy to come back? Street muts can't be taught new tricks. You can't teach an ignorant urban jungle manimal civility. Even correctional facilities can't do it. You think getting caught and you begging them to go away and never come back will set them straight?
No I don't think murder is ok but sometimes you run out of options. Do you live in fear for the rest of your life? Never knowing when this moral lacking leech of society will return to take or hurt what is rightfully yours to protect?
What about you? Do you think self defense justifies murder?