I think we need to consider the origins of these United States. Remember that many of the colonies were formed by people fleeing religious persecution in Europe. That'sat least a large part of why the American attitude toward wacko religions is more tolerant (in a "hands off, let 'em do their thing" way) than that of the Europeans, who can simply revert to their old way of dealing with different ideas.
While I think that is part of the reason, I wish it was otherwise. I wish that the secular authorities would permit whatever silly spiritual beliefs and practices a person wanted but keep a cold, unblinking eye on the pyhsical consequences of those spiritual beliefs and actions. Thus, charitable works would be encouraged, and religious filicide would not.