It contributed to their deaths in the same way covid contributes to the death of someone with underlying conditions. Or what, will you say that it was the underlying conditions that killed them, and not covid? ;)
Very old people were not part of volunteer group, so this vaccine do have more severe side effects than extrapolated. They are changing the regime and skipping some of the frailest due to this. The vaccine will still provide protection for most.
How do you know it contributed to their death? How would it do so? There are clear ways underlying conditions can contribute to death by covid, but I’m not aware of any such thing with the vaccine.
We are pretty sure that Covid caused the vast majority of those excess deaths