OK, first, I am not convinced that socially responsible is strictly a moral position. Disease vector analysis is just an analysis on a directed graph. In this case there is a strong mathematical model, with scientific evidence, that not vaccinating children can harm other children. Because of this I am questioning your analogy, since in the case of the draft there is not a non-opinion social component.

Instead I analogize with drunk driving -- significantly fewere drunk drivers equates to significantly fewer 3rd party injuries and deaths as a result of drunk drivers. Similarly in the vaccination case, there are 3rd parties who stand to suffer from the actions of those who do not receive vaccines.

Edit: I forgot to put my second point, which is:

I agree with your analogy in that those who stand to benefit should be closely scrutinized when advocating a position.