After reading the article, I think it boils down to

a) Poor/lack of understanding of who the actual users are e.g. these are systems that will be used by both the young and old people, especially older people in the early stages since they are the ones at the front of the vaccine line; worst case, the system should have been optimized for them.

b) bullet a then leads to poor requirements e.g. given that most libraries are shut down (lots of elderly people get help with online stuff at community centers/libraries), requirements should have included less rigidity (on errors) or a module that is fun and friendly that walks people through it, system should be designed with 'plain' mobile first in mind, and account for a person being both a patient and an admin, etc