The discussion is about loss aversion phenomenom as defined and used in psychology. It is not about what you intuitively guessed from how it sounded like to you.

But also, you horribly simplified military and soccer strategies too. Fun fact: army can decide for offensive strategy, because defense would end up in bigger losses. They may also go for defensive strategy despite bigger loss, bc some other reason.

Lastly, no not every kill to protect yourself is self defense. That is not how law and sentencing works.