I am not following what you are saying in your critique of her post. My understanding is this.
You will have a chart of hospitalizations or deaths from the CDC. The pair breakdown is vaccinated and unvaccinated. However because of how they define who counts as unvaccinated (it includes people vaccinated within 2 weeks) some of the hospitalized or deaths in the “unvaccinated” column are actually vaccinated
Basically, she is going from a "could have" to "it definitely happened and proves something" when the study doesn't show it.
It is not just "vaccinated" and "unvaccinated", there are "partially vaccinated" in the study as well, since it takes time for the vaccines/therapies to take effect. My read of this is she is mixing up "partially vaccinated" with "unvaccinated" and claiming "vaccinated" are counted as "unvaccinated" when the people she are taking about are actually "partially vaccinated" in their own category.