I'm sure one could dig up more appropriate figures that exclude accident, homicide, etc. But the reference class is still going to be pretty broad: if Roberts had committed suicide, had developed cancer, had a stroke rather than heart attack (or whatever), had a fall, people would be speculating on biological roots

I would have to agree with that, however some causes of death are more suspicious than others. In this case, he died apparently died suddenly, at an age where sudden death is rather unusual in people with no self-reported history of serious health problems. Also, this kind of sudden death is usually the result of cardiovascular problems, i.e. heart attack or stroke. Last, he was known to be regularly consuming a lot of concentrated fat on a regular basis (half a stick of butter a day; and perhaps olive oil and flax seed on top of it); fatty foods have long been suspected as playing a role in cardiovascular problems, that they cause lipids to build up in the blood stream and clog up the works.

It would be very tricky to do the equations, if it's possible at all, but it seems reasonable to think it's likely that his supplement regimen played a role in his demise.

As I've pointed out, the prior is quite high that he would die in a 'suspicious' way.

Well do you agree that what happened is more 'suspicious' than if he had died at the age of 75 from lung cancer?

No, and I refuse to give one on a problem which reflects motivated cognition on the part of many people based on heavily-selected evidence & post hoc reasoning.

Suit yourself, but it strikes me as confusing that I would make a claim and you would respond with a calculation which seems to address the claim but actually doesn't. It makes me think you are trying to subtly change the subject. Which is fine, but I think you should be explicit about it. Otherwise it seems like you are attacking a strawman.