Can't tell if you are trolling or what. Scientists can be wrong and they get peer reviewed for every publication they make and corrected on spot. You know who is "wronger" (if I may to make this word up) non scientists.

If a scientific research proves to be wrong by peer review it stops of being a science right here and there.

If science its not objective it's not science. There is no other way around this phrasing. You are talking about the simulations made about the impact that Covid-19 will have. Thats statistic science and it works inside a frame of marginal errors. Facts will come when the virus is done its cycle throughout the global population, and not before. We are in the speculation phase of statistics.

As for the link there is a term called cause and effect. Pre-existing conditions does not kill you on their own. If you are obese you wont asphyctiate to death from the extra weight on your lungs but your liver and kidneys will suffer and if you get a pneumonia it will kill you most than certain or put you in a coma and mechanical support for quite a while causing even more troubles. If you have diabetes you will be alive until you get the flu then you are most probably going to die who killed you? Diabetes or the virus?

As an example You are swimming in the sea you could be eaten by shark or get drawn but most probably you will be just fine and swim another day, Now if a shark mauls you the sea did't kill you cause there where probably a lot more people in the same sea same beach same day. The shark eat you which was the easiest target.