Yeah, I've heard that myth. It was started by some conservative protesters.
Well, partial myth. If they die from a covid-19 related disease then and they test positive then it's declared a Covid-19 death. But if someone had pneumonia, and they contracted covid-19 the next day, then died the day after, it would likely still be classed as a Covid-19 death.
But there's the other side of it. If someone contracts covid-19 and dies then it's usually classed as a Covid-19 death temporarily until an autopsy confirms. If the autopsy comes back with another unrelated cause of death, then it's removed from the official death toll. But it can take 2 weeks for autopsy results to come back so there will always be some figures that aren't accurate.
But then there's the other, other side of it. If a person contracts covid-19, dies at home without going to hospital, then by the time they carry out the autopsy they may not find the virus so that death gets classed as a non-covid-19 death.
Then there's the other, other, other side of it. In China if anyone contracted covid-19 but showed no symptoms then they weren't classified as covid-19. If they died from Covid-19 it still wasn't classed ad covid-19 because they were never officially recorded as a Covid-19 case.
In the end with lag time between contraction and death, and lag time between confirmation, we're not going to know the actual numbers until this is all over.