In principle, I think moron parents should have the right to make medical decisions that endanger their children’s lives, like refusing to have them vaccinated. If they want to needlessly subject their children to horrible diseases that have been practicality eradicated from the developed world, I suppose that is their choice.
But, I think it is insane to turn an issue that only affects a tiny, irrational, misinformed minority into a litmus test issue. It is a lot like what the Democrats do when they pander sexual deviants.
Do you feel the same way about parents subjecting their children to bad food and bad sanitation? At what point does the child have rights that the state needs to protect?
I am inclined to think that refusing to give your child a known protection against very serious and deadly diseases constitutes a rejection of parental obligations.