I think the term anti-vaxx means: "People who believe medical treatments should not be given or forced based on blind faith and should be subject to intellectual inquiry, evidence, logic, reason, and open debate and discussion and even democratic discourse prior to political action" But, I don't call that anti-vaxx, I just call that a rational human. Being rational is a choice, so calling this a mass formation psychosis does not in any way take away responsibility. Giving into fear and choosing not to think is a choice. There is an intersection between psychology, ethics and free will.