Preventing degenerative diseases with a good diet like Hunza/Okinawa diet since birth is one thing. But healing from one those degenerative diseases is another. Diet is key in recovery, but it's not gonna be enough in advanced stages.
Juice fasting and enemas and other "shitty" stuff have healed many of terminal diseases, and it healed me when no diet was making any difference. You obviously have no experience treating those advanced diseases to make a statement like that.