What is the rationale of those who want to make self defence illegal?
It's because they bever be in such situations that involved molestation and harrasment including life threatening to the point of death, somethings happens and we take a wrong decision as approach to administering the situation because we are not the one or victim involved, self defence is legal and under the court of law it's is allowed in constitution, but there must be a tangible evidence to ascertain the situation under a murder or life threatening self defense, because somethings were better experienced or witnessed than making a wrong judgement on the whole situation, engage in self defense to get yourself secured from any things that serves danger to your life.
You do not need to die or proof that you would have died from the attack or whatsoever but the court will be reasonable enough to know if the attack would have caused you death based on the weapon of attack and what weapon was used for defence. Self case is complicated because provocation may still be looked at and if the measure of provocation is proven or perceived to have been calmed and you go attacking in the guise of self defense maybe when the attacker was sleeping already, the court may not admit that evidence.