Billions of people truly believe in the existence of a super-natural creature up in the sky. Some devoting time, energy and tons of money. Not something that should surprise given the scale.
This is a facile and offensive argument. Non-atheists are not the intellectual equivalent of Holocaust deniers or antivax advocates. All you're doing is inviting religious flamewar, which is not allowed on HN.
I say give anyone the freedom to have any opinion as long as he doesn't incite violence or act on it.
For antivax it is really a complicated one. I don't have a problem with antivax advocates but I have a problem with parents that don't vaccinate their kids. And I think the government should act on the best interest of its minor citizens.