At what point does faith become insanity?

[Paleophyte]

To determine when someone is insane, you'd have to decide on some criteria for what constitutes insanity. So I'm asking a pertinent question.

If you believe in some essential human nature, and that we can judge when someone is deviating from that, you might be able to judge who is insane. However, standards like that in the past have tended to change. For example, it wasn't long ago that a person with a penis who said he was a woman would be considered delusional. But things have changed. 

Is someone necessarily insane if they are a danger to themselves or others? Or are some sane people just dangerous? If someone's mental state makes him unable to function in society, is that a sign of insanity? Or might there be societies that are so insane that sane people can't function in them? 

These are legitimate questions.

I agree. I just don't think that it helps your argument except to illustrate religion's social and cultural delusions.

Imagine a murder trial where the defendant volunteers the information that he regularly participates in ritual cannibalism. His lawyer makes no attempt to stop this admission, the prosecution doesn't bother to examine the point further, the judge doesn't bat an eyelash, and the jury simply nods and smiles. Does nothing in that scenario strike you as just a touch surreal?

Now imagine the same murder trial where the defendant states that he is a Christian who regularly takes communion.

These individuals hold a belief that is not simply counter-factual but a violation of one of the most basic taboos known to anthropology. Under any other circumstances the notion of magically transmuting wafers and wine to flesh and blood and then consuming them would be utterly repellant and good grounds for having an individual's mental well-being called into question. But rebrand it as religious tradition and it becomes entirely acceptable. The ability of religion to utterly supplant social norms so thoroughly and pervasively should be a concern for any thinking person.

It's noteworthy that this example utilizes a relatively harmless Christian tradition, at least in terms of the direct damage to the public. We haven't delved into some of the really ugly bits to find something that looks to be about seven beer short of a six pack.