On coffee there is no study where an animal model such as rats have been given coffee with or without caffeine compared to a control to see if it extends lifespan. Show me that study to convince me of a measurable health benefit.

Exactly my point. We don't know. Further the only way to know for sure would be to actually do it as a human study not on animals. We do have the data for coffee, hence we cans say that coffee has benefits.

The beneficial part of cannabis has been isolated.

Really?

You speak in absolute certainties. That is not scientific and it is not how research works.

Find and isolate the beneficial part of coffee and do trials with that to convince me that something in coffee is beneficial.

Better still why don't you do the same and prove that it is harmful? You seem to be absolutely certain of that with a religious zeal.