Australian Health Department quotes Covid study and it's misleading

In the past, I have asked the Health Department why they think the Covid vaccine is fit for purpose, because it didn't stop transmission and it didn't stop infection. Professor Kelly and others would always reply that it reduced the severity of disease. So I've asked the Health Department in prior questions on Estimates for these figures and the response I got was that the unvaccinated death rate from Omicron was running at about 32% for people over 70, versus the unvaccinated death rate for people from Alpha, that had a death rate for people over 70 who are unvaccinated, of about 22/23%. So the death rate is almost 40% higher for Omicron than what it was for Alpha. I then proceeded to go back to Estimates and ask Professor Kelly why these figures were higher for Omicron than they were for Alpha. He replied that he conducted a study, or his department conducted a study, of 3.8 million people. This study was by the National Centre for Immunisation Research and Surveillance and and is