Personally I think it is never justifiable but I've heard many people with a different opinion on this topic so I'm curious about what you al think.

I personally share your opinion.
I do however understand why some people disagree...
Like to hear those people and their reasons though!

I personally beleive it's not justifieble because of the irreversablility of the act and the example of violence. But what if you know absolutely certain that someone has committed grave offences and the mere existence of this person creates a lot of tension and unrest in society, is it then still not a possibility? For example a leader of a genocide, is the death of that person not the only thing that could reassure the victims that there has been a break from this horrible system?