For hospitals it's the federal EMTALA law which makes it illegal for hospitals to deny emergency care on the basis of vaccination status. If a patient shows up with unstable vital signs then the hospital is required to at least stabilize them. For COVID-19 patients that's usually based on respiratory distress or low blood oxygen saturation.
So, we essentially have mandates to "treat" with no corresponding agreement on defining any mandates to "prevent". Prevention mandates could be a tapestry of options and defined within specific contextual and cultural boundaries. But having nothing on the "prevent" tilts the scale entirely to obligatory treatment and clearly feels imbalanced.
https://www.cms.gov/Regulations-and-Guidance/Legislation/EMT...