>There's still a (naive?) liberal side to me that thinks free expression, even of profoundly stupid ideas, might be a net good for society,

I was thinking today about the high costs of the stupid idea of anti-vaccinations, in this case children that are not at fault will die because of this ideas, should we block them or we should put billions of dollars into educating this people instead of using this money for better things.

it is not a black or white problem but in this case I personally think is better to block this idea.