Here is one way to argue this.
Stealing is stealing. Correct? Stealing is not fishing, stealing is not sex, stealing is stealing. Yes? Everyone agree? Ok good.
Taking something that does not belong to you from someone who possess it is considered stealing. Yes? Ok good. Moving on.
Stealing is wrong. Yes? Ok good.
Murder is murder. Correct? Murder is not eating, murder is not driving, murder is murder. Yes? Everyone agree? Ok good.
Taking someones life is considered murder. Yes? Ok good. Moving on.
Murder is wrong. Yes? Ok good.
A woman who has been beaten everyday of her life finally exacts revenge on her husband because it's the only way out for her, by killing him. This is murder. Yes? Is it wrong? Yes. But is it justified? I would say yes. BUT it's still fucking wrong.
A 10 year old boy shop lifts from Wal Mart. He is hungry. He is homeless. But he stole something. Is this 'stealing'? Yes. Of course. Is it justified. Yep, sure is. BUT it's still fucking wrong.
Thread is complete. Go about your business.