There is certainly a lot of spiritual waffle on nikyo here. If in doubt - keep it simple. Of course nikyo hurts. Martial arts are about destroying people. Get used to it. The pain in nikyo is about as bad as pain gets for most people and that's why we like it. Admit it. For me, a good nikyo is one that hurts like hell when on, yet afterwards, little to no pain lingers = no damage. That is good nikyo. And to have no lingering pain you have to find a way to do it with minimum force - that is the real skill.
Martial arts are not for destroying people for me...I train for self-defense, personal development and fun. So speak for yourself.
Nikyo hurts some people and doesn't hurt others. I do like the pain of it and the fact that it doesn't cause harm but compliance.