This logic is brain-dead. By definition, self-defense is the exercise of your right to defend yourself through the use of FORCE to stop another individual from harming you. It necessarily requires you to violate the other party's right. Point in fact, it is possible for a person to FORFEIT his right by course of action. If you violently attack me you FORFEIT your right to live when I exercise my right to self-defense. THIS IS WHY THE LAW PERMITS THE USE OF DEADLY FORCE IN CASES OF SELF-DEFENSE.
I think you misunderstand; sourcery's point was that self-defense does not imply the right to endanger the lives of innocent people. And to a significant measure he's right. On the other hand, risk is usually a quantitative rather than qualitative phenomenon. Nearly anything one might do in many self-defense situations would pose some non-zero risk if injuring or killing an innocent person. Even if one has a clear shot at an attacking criminal, if there's also an innocent person nearby there's a non-zero chance that one's gun might explode, injuring that person. To be sure, such a risk would probably be very slight, but it would nonetheless be non-zero.
I would suggest that a reasonable guiding principle would probably be to consider whether the risk imposed to innocent parties as a result of one's action was greater than the threat posed to them by inaction. If a wild animal is severely mauling someone, someone might be justified in shooting at the animal even if they had a 20% chance of hitting the person being attacked, since the alternative would probably be a 100% certainty of the person being killed.
What this illustrates to me is the wisdom of the advice I was given in my Nevada CCW class: when the police arrive, say nothing more than "I've done nothing wrong here and fully intend to cooperate with your investigation, but I intend to say nothing about this incident until I have spoken with my attorney. I'm sure you understand".