Except that in reality there aren't 20 vaccinated people and 5 unvaccinated people with COVID. There is 1 vaccinated person and 49 unvaccinated people with COVID.
Regardless, your argument doesn't make any sense. If anyone -- vaccinated or not -- has COVID, they should be required to stay home. If an unvaccinated person does not yet have COVID, we should push them to get vaccinated, because then they will be much less likely to get the disease, and if they do get it, serious illness or hospitalization will be vanishingly unlikely.
Vaccination also reduces the "breeding ground" for mutations. At this point it's critical that we slow down the creation and spread of new variants that might do a better job of getting around our existing vaccines.
