Not vaccinating does potentially cause harm to others through infection, and someone unvaccinated can only fully prevent such harm by completely avoiding any contact with humans they are not living with; furthermore, such harm cannot be reliably attributed to the perpetrator, so punishment is hard.

Hence, it is reasonable to outlaw being unvaccinated and going out of the house.

Unvaccinated people aren't going to hurt any vaccinated people. It's no worse than being fat or smoking; the worst thing you can say is it increases people's health insurance costs.