I disagree - living in a society where we watch someone get murdered when there is an opportunity to intervene is abhorrent to me.
Way to shift the goalposts. The shooter was not watching Gildersleeve murder anyone when he killed Gildersleeve.
And your hypothetical misses the mark - any competent police officer would have shot Gildersleeve.
Assertion without evidence. Discarded.
Moreover, if the person shooting Gildersleeve by definition was breaking the law then he'd be incarcerated and awaiting trial - not released after the police conducted an interview. If you think there are other factors involved in this case beyond your implication that this is prima facie a violation of law then you should cite some corroborating evidence.
I stand corrected. In Illinoise you can use use up to lethal force to stop a forcible felony.
I think you're wrong about at least one of your definitions.
http://rationalwiki.org/wiki/Moving_the_goalposts
http://deathpenalty.procon.org/view.resource.php?resourceID=004927
So which is it? If we must witness a capital offence, then ipso fatso we must witness someone being murdered by the very definition of capital offence.
My 'assertion without evidence' is as plain as the nose on my face. Even a half-assed attempt at finding what happens in cases of armed gunmen committing a robbery when the police are on the scene mirror this case: http://www.mercurynews.com/bay-area-news/ci_27763788/santa-clara-officers-kill-suspect-they-see-rob