Naturally "the Tonga people of Zimbabwe grow and smoke ganja as part of their culture and they live long". The Babylon system would like to scare us all out of acting like Rasta's by having us place more faith in its easily-manipulated science & technology than we place in H.I.M., Our Creator who bestows the Gift of Life upon us.
We all ingest all kinds of naturally-occurring "poisons" regularly which is why JAH endowed our bodies with magnificent immunological and self-purification capacities. The current state of human understanding of toxicology among experts is actually very rudimentary and limited (and even more so among laypeople). For example, everybody knows that arsenic is a deadly poison at high does, but how many know that it is actually an essential micronutrient for humans and that levels of up to 20 milligrams of this nutrient can be found in a healthy human body?
We should listen to what JAH the I-ternal sey to us and only take with a grain of salt the latest health science findings of the Babylon system (which have a funny way of changing every few decades).