I think people fully understand it. What people IMO fail to realize is or take responsibility for is that once you put your hands on someone FIRST. You don't get to determine their level of response and you not a victim.
Can people go too far? Hell yes they can. At the same time though just because a person went too far that doesn't make said person innocent in how the shit became physical in the first place.
Im not saying you can tell someone else how to respond. But the idea that any level of response is ok and justified, which has been said in here, is wrong. Hence why if somone pushes you and in turn you kill them your "well your honor i can respond however i want" defense will go nowhere