Yes, most young people who died horrible deaths was before vaccines were available for them.
After getting vaccines, the immune system is not likely to go into overdrive when virus arrives. Because immune system has already been made familiar with signatures of vaccine proteins. Same thing takes place with a mild invasion of virus from which you recover.
From what I have been reading it is the over-reaction by body which causes the most harm to vital organs, especially the lungs, where covid virus invades first through respiratory passages.
Lockdowns are harmful for the same reason. You never have a chance to inhale a small dose of virus and build immunity.
You can’t guarantee that the vax would have changed a thing for them because you can’t go back in time and do a redo.
That’s just wishful thinking and proves NOTHING.