Because vaccination / immunisation prevents diseases and not vaccinating/ immunising allows opportunites for diseases to take hold in our communities again and that puts MY children & YOUR children at risk. The decisions that we make for our children have wide ranging effects in our community for EVERYONE.
Hmm.. funny that the most recent cases of polio and whooping cough were found only in those who were vaccinated...

Well, if this is the logic that allows others to force things on other people, I want it to be compulsory that parents MUST make all their food and cleaning products at home from scratch using all-organic products so they don't clog up the medical system with their health issues - because that effects the whole community too.