Anti-vaxxers are often characterized as misinformed, and people like Mr. Hildebrand are often characterized as exploited by leaders of Children’s Health Defense when they are vulnerable. But that doesn’t give the people I met at the conference enough credit for the agency they exercise in their lives, or for how sincerely they hold their beliefs. They are there by choice because they accept the group’s worldview. In that world, they feel believed and valued, and are encouraged to think of themselves as brave instead of scared.