As far as I can see, the original point still remains: if the person would have lived without corona-virus and also would have lived without obesity (and probably better and longer too), who is to say which one is the "primary/secondary" health condition? What killed him?
I'd say the correct answer is, "both things". The combination.
Yes, I totally get this point and agree. You can't catch obesity by passing someone on the street.
Just to play devil's advocate however, there is still a point here. It is "what level of social upheaval or limitations on freedom are we prepared to endure to save X amount of lives?". If someone is obese, the measures need not be "sweeping public measures that effect everyone". Only the obese people needs to be forcibly put on a diet and exercise regime to solve the problem. Would that be acceptable?
Obviously not. But it does highlight the extraordinary social and economic sacrifices that some are apparently willing to endure to save far fewer (and typically very old) people in the case of corona-virus.