It is pretty simple. There are MYRIADS of reasons as to why one may choose to NOT get the vaccine.
Because you can't understand them, doesn't mean they aren't valid reasons.
Maybe you should consider that fact.
The point is that there are hundreds of 1000s of healthcare workers in this nation, very well educated who seem to have taken a stance so far against getting the vaccine, up to 22% of the highly educated medical professionals have decided they believe that it may not be as safe as YOU believe it is.
You keep repeating like a parrot
"I don't see a good reason as to why they don't vaccinated".
Well you know what, that falls under the category of TOUGH NOOGIES.
Perhaps they don't need to explain it to YOU, even though you believe with all your heart that they OWE you an explanation.
Greg doesn't OWE you an explanation either.
Its called HIS business, and even though you think they do owe you an explanation, they don't.
It is THAT simple.
I don't get a yearly flu vaccine. That falls under the heading of MY business, not yours.
We still live in a free society where the gov't can't FORCE me to put something in my arm that I don't want in there.
I answered YOUR questions above, so here's a question for you.
Do you have the capability to understand that others in society don't owe YOU an explanation for their decisions in life?
If you don't want to get sick, then YOU get vaccinated.
If you don't want to get sick, then YOU wear a mask.
If you don't want to get sick and you see someone without a mask and you're afraid, then YOU stay away from that person.
If you don't want to get sick and you're terrified of getting sick then YOU stay home, and leave the rest of us alone.
That's pretty simple advice don't you think?
Its this simple, I don't owe YOU jack shit in life. 
And that should answer your simple direct question above when you ask
"what is the point you are trying to make". Is that clear enough for YOU?