Religion is a Delusion/Mental Illness

[Razzle]

With all due respect, I don't think you know what you're talking about.  Name three diagnoses that fit the pattern you are claiming.

The very definition of "mental illness" ties it to social norms:

A mental disorder, also called a mental illness or psychiatric disorder, is a mental or behavioral pattern or anomaly that causes either suffering or an impaired ability to function in ordinary life (disability), and which is not a developmental or social norm.

http://en.wikipedia.org/wiki/Mental_disorder

"Impaired ability to function in ordinary life" means that one has a problem with dealing with the society in which one lives.  And what will be incompatible with ordinary functioning in a society is largely a matter of the society in which one lives.

That's exactly how we determine whether anything is an pathological state, not just mental conditions. 

Blindness would not be classed as a disability, and various causes of blindness would not be classed as illnesses and disorders, if all humans were born blind and our society was set up in a way that accommodated that. So what? Should we not try to find cures and treatments for blindness, and should we not give blind people disability status and the support and protections that entitles them to, just because it wouldn't be classed as such if everyone were the same? 

Not being able to fly is inconvenient and sometimes causes death, but it's not classed as a disability or disorder, because it's the norm not to be able to fly, and nothing in our daily lives makes it a problem because society is set up in a way that fully accommodates our inability to fly. Do you think it should be otherwise? How do you propose we define which conditions of the mind/skin/eye/lung/liver/ are,pathological and which are not? 

There are also cases in which something would be classed as an illness or disorder even if everyone did develop it - such as the plague. Communities didn't stop treating it as an illness to be cured just because all of them had it. That's because it's more than just impairing, it's deadly and causes suffering directly. The same is true of mental disorders. While there are some which are more like blindness, in that they're only impairing in a particular context (which happens to be a universally applicable context, unless there are mole-people we don't know about), there are other mental disorders that would always be classed as disorders even if there were a pandemic, either because they cause death (e.g. anorexia nervosa, like heart disease), or suffering directly (e.g. painful depression, like painful psoriasis of the skin) and/or are so incapacitating that humanity would die out if everyone had them, e.g. schizophrenia, like paraplegia.

What's really happening is a double-standard against mental disorders, and it's just one of many. Every criticism that's leveled at psychiatry can equally be leveled at haemotology or opthalmology, yet suspiciously never is.