When is "Self-Defense" a deflection from other conversations?

I have heard more than one conversation lately about self-defense, which is natural in the wake of this week's events. While that question is necessary in our fallen world, I've seen it misapplied in various ways. So before taking a look at self-defense, the first step is to be sure that "self-defense" is the topic on the table. 

If the question is about the ethics of self-defense, that question is specifically about defending the self: the one person asking the question. If the person being attacked is responsible for the defense of others, it is no longer a question of self-defense and the person does not have the latitude to decide on personal preference alone. For anyone in a responsible position, there is a duty to protect those under our care. 

Again, if the question is about the ethics of self-defense, that question is about defending from an attack. It does not cover a "pre-emptive strike", something that comes up more often in international conflicts. The question of self-defense does cover the question of being the initiator. This is not to comment on whether it is ever justified to strike first, but to state plainly that striking first is not a question of self-defense.