It has to be great bodily harm, and self defense always depends in the "totality of the circumstances." That's why I said "in most cases."
The "totality of circumstances" is a huge angry mob that has committed countless crimes, including arson, assault, theft and jaywalking.
Kyle didn't know that Rosenbong was a literal psycho-kiddy-diddler, but what he did know was that the guy was extremely aggressive, confrontational and violent.
Rosenbong was not trying to give Kyle a wedgie. Rosenbong was not just trying to give him a slight slap on the arm. He was blatantly obviously and beyond the smallest shadow of a doubt in it to cause great bodily harm to Kyle. Everyone thereafter was literally screaming bloody murder and there is absolutely no doubt to anyone with half a brain (lol Rosenbong) that Kyle would have been lynched on the spot by an angry mob.
Had Kyle been some sort of mass shooter that literally opened fire on people for no other reason than bloodlust like the media paints him and the people were trying to stop him from committing more murders, they'd be justified in their actions, but he wasn't. He legally defended himself from an attacker, that was trying to -at the least!- cause him great physical harm. He was no threat to anyone thereafter. He was not aggressive towards anyone thereafter. He did not threaten anyone with his gun at any point. He did not open fire at anyone unless he had to defend himself.
People realized someone got shot and they made a stupid decision. Yeah, it's a shitty situation, but things escalated and at no point is Kyle (or anyone else in that situation for that matter) obligated to just go into fetal postion and allow the mob to punch them to death with skateboards. The people attacked Kyle and he defended himself. Full stop.
In what jurisdiction is proportionality not required for self defense?
Germany, for instance. And before anyone asks:
German self defense laws are essentially what clapistanis call "stand your ground" laws.
