Must viruses generally affect the genetically 'weakest' in any given population.
It really is simple biology, a virus doesn't have feelings, it just does what it does.
Our single biggest mistake was the NHS discharging 20,000 'bed blocking' old people into care homes at the start of the pandemic. That allowed the virus to infect (and kill) far more old people than would otherwise have happened.
What's really interesting is, the fact that more younger people are currently in hospital and fighting the virus, rather than dying, they aren't seen as 'bed blocking' but patients needing medical care. The institutional bias against old people and how they are viewed will eventually be looked at in the public enquiry, I'm sure.
One of the long term consequences might be more people living in multi-generational households; especially as it stops the state removing the assets to pay for the care. It might not, but I would think given how they've been treated, I'd be looking long and hard about it if I was in that position.
And back to the OP, it proves that the tiered approach to the vaccination makes sense.