That's just another idea that leans more toward an individual belief than a non-negotiable one for all Rastas. It is a more orthodox/traditionalist held belief. It's just an extension of the idea that your body is your temple, your temple is divine in nature, therefore you must respect it. That's why it must be intact to get to heaven. That is probably the main reason the concept of ital and ital living exists. Why many Rastas are vegan and vegetarian. Many people rally around those principles and organize around them. Many don't. I do know It doesn't originate in Rastafari. I think he did go to the doctor though, and many argue that his death was an assassination. In that line of thinking, his beliefs didn't kill him, his assassins did.
Just depends on your view.
Thanks for trying to be unbiased and using an ethical lens to look at this whole debate. It means a lot.