Humans are complex beings, mulitlayered, individual and at the same time part of a group.
This sentence alone could give you ideas of why we believe the process of self defence must be wholesome to be powerful.
Your personal life is influenced and triggered by many factors, such as age, health, ethnity, personal development, gender, culture, social status etc. - all this gathered together in your personal experiences.
And personal experiences are the clue why self protection is always individual.
Experiences mainly manifest through emotions, which then form beliefs and self-perception. Through education we deepen or loosen (which is unlike eleminating or changing) the manifestation. To put this into context of a threatening situation, let us come straight to the point: