As a father of a once very medically fragile daughter, when a common cold would send her to the childrens hospital for a month long stay where she would be npo and on tpn, a bug like measles could have killed her. Some parents have the choice to not vaccinate their healthy children, and would rather take that risk of getting sick. Unfortunately their potentially minor sickness could be a death sentence for others in the community.
I hope she's doing very well! And I agree with you.