Because, while the vaccinated may have better protection against getting infected themselves, they may still be infectious to others.
And what happened to the last 100+ years of vaccine science, not to mention the last year of research on C-19 showing non-Symptomatic cases not spreading the virus?
Like I said, if you want to say that we need to get the vaccine while at the same time say we can not get back to normal even after doing so, dont be surprised when people don't see the need to get vaccinated. You are setting up the excuse for people not to get it; it is just a logical conclusion to not do so if you imply it does not work by saying it does not allow us to get back to normal. And lets not forget the countless Dems telling us back in October that we should not trust the vaccine due to Trump's involvement and the Tuskegee experiments.
It is the Dems that have sown this seed of vaccine denialism, and no Dem has actually done anything to try and fix it.