Medical triage is not typically done on "groups".
When you go to emergency, the triage nurse does not say "okay, we're seeing everyone over 60 now, over 60 to the front of the line."
But for goodness sake,
I did not and do not reject the notion that you could prioritise some groups over others. I just said it is not the same thing as medical triage that considers individuals and their unique circumstances.
Not when there is a large number of patients due to an accident, fire, or similar disaster.
In such cases, when there are a large number of urgent/potentially urgent cases, then yes, whoever is working triage will organize them as quickly as possible according to the urgency/potential life threatening need. It could be: whoever was in vehicle A or in Chem Room 207 or anyone under 15? Or Over 65 or with asthma or unconscious, etc.
The pandemic is an massive scale medical emergency. Massive numbers of patients need to be vaccinated. Even if we had sufficient doses to vaccinate everyone in every location globally in a well staffed, well supplied medical clinic, we would be unable to vaccinate everyone simultaneously and in order to avoid chaos, we'd have to set parameters that made sense. The parameters that various states set make sense to their health departments given their populations and various demographics within the state and how they have seen the disease progress over the course of the year or so before vaccines were widely available. They identified which groups had shown increased vulnerability to disease requiring hospitalization or death, and set priorities according to that data.