Don't get me wrong I think it's perfectly valid to use statistics for estimating the impact/IFR but you can't like many people with an agenda pick and choose your counting methods.
We see this happening now in the US with unofficial deaths getting lumped into the C19 deaths, some of which may very well have been flu.
If someone has cancer and then gets a bad cold and dies, what should the cause of death be? Or what if they fell, etc.?
They also recognize a a contributory cause of death, defined as “a significant condition that unfavourably influences the course of the morbid process and thus contributes to the fatal outcome, but which is not related to the disease or condition directly causing death.”
Because that is what is happening when you take an extremely sick person who finally died and slap a "death by covid-19" label on them.
When influenza deaths are estimated each year, the models assume that a lot of people will die due to the virus but the cause will be recorded as heart failure or pneumonia without etiology. From the perspective of the epidemiologist, they are influenza deaths, even if they were old and frail with bad hearts.
If someone ends up catching pneumonia because their immune system was compromised as a result of immunotherapy, pneumonia was the direct cause of death and the cancer lead up to pneumonia.
The fact that we have to have this argument about basic death statistics is depressing. If you really wanted to play around with the numbers like what you're suggesting, you could easily make it so covid-19 causes zero deaths just by looking far back enough to find a contributing factor. Like age, immune system issues, other injuries, obesity etc.
Or that cancer causes zero deaths...
What are those?