Umm... you definitely are confused. Other children at risk are ones that can't be vaccinated due to genuine medical reasons. Vaccines do not stop you from being infected. They will reduce the severity and length you are infected but will not stop it.
I agree that they shouldn't be mandatory but educating people is extremely difficult, especially when it is education in moderately difficult to understand science. We have people that believe the earth is less than 10,000 years old and evolution by natural selection is equivalent to a chimpanzee giving birth to a Homo sapien.