The medical conditions folks should probably be staying locked down. The vaccines aren't a guarantee that people around you aren't contagious; just a low likelihood that you will be very contagious if you get it.
If they're around lots of people, even vaccinated folks, they'll still catch covid and die
If 99 out of 100 people are vaccinated, the remaining person should be fine. "Should be" is the key phrase here—there are no guarantees in life—but while vaccinated people can still spread the virus, they're still much less likely to do so.
It's all a probability game. Add to this that the sole unvaccinated person is the one most at risk in any given setting, and I'm really fine letting them make their own choices.
If they're around lots of people, even vaccinated folks, they'll still catch covid and die