The thing is, with this idea that "parents should be the ones to choose" whether or not they vaccinate their kids, is that it only works if that parent and child live in a bubble and the parent happens to be an expert in immunology. As a parent, you get to choose lots of things for your child - their name, the clothes they wear, the school they go to and so on. However, if your child broke its leg and you refused to get it set, you would be thrown in jail for negligence and abuse, regardless of your views as to how "natural" a plaster cast is. Just because you are a parent, you do not get to decide how biology works and you do not get to put another humans life at risk, got it? The average parent does not, and is not expected to, have any in-depth medical knowledge, that's why we have doctors in the first place. Then we have this issue of herd immunity that we touched on earlier. Deciding not to vaccinate not only puts your kid's health at risk, but everybody else's too. In the same way that you're not at liberty to choose to smoke indoors anymore, because it's bad for public health, vaccination is also for the greater good and choosing not to is a selfish act. Simple as that.