Like so many other "lessons" propounded by TWI, 4 crucified was meaningless drivel. If one hasn't learned to treat their fellow man with the respect and equity with which they, themselves, would yearn to be treated, they have leaned nothing at all.
You can learn to ride a bike, put it away for 50 years, and climb right back on after all that time, still possessing the ability to ride a bike. Not so with interpersonal relationships. There is no end point. Every day is another chance to do better than you did the day before. This concept of becoming a better human being is lost to TWI's endless pursuit of pedantic excellence.