They’re conflating two different things.
They’re entitled to believe that faith in God will save their souls. I don’t mind it if they do.
When it comes to their bodies, however, here on earth, it’s obvious that healthcare choices you make can either lengthen or shorten your life. Or increase or reduce your risk of death. Science and modern medicine does a pretty good job of describing how the human body works, certainly better than the Bible.
Getting vaccinated falls in column B, not column A. And going unvaccinated isn’t just a risk to yourself, but the community as well. That’s where I have a problem with their recklessness.