"It's irrational to be religious" ... Saying "amen" to this is ok?

Practically everybody in the US loves to beat up on Scientology and their crazy believers, best personified by Tom "jump on the couch" Cruise.  Some of the latest reports are way more than hysterically funny, and should worry us that such bizarre beliefs and practices exist, and grow.

Scientology easily comes across as irrational.  But, then every religion has its set of strange beliefs and practices.  Jared Diamond writes:

[A] religion’s adherents firmly hold beliefs that conflict with and cannot be confirmed by our experience of the natural world, and that appear implausible to people other than the adherents of that particular religion. For example, Hindus believe there is a monkey god who travels thousands of kilometers at a single somersault. Catholics believe a woman who had not yet been fertilized by a man became pregnant and gave birth to a baby boy, whose body eventually after his death was carried up to a place called heaven, often represented as being located in the sky. The Jewish faith believes that a supernatural being gave a chunk of desert in the Middle East to the being’s favorite people, as their home forever.
No other feature of religion creates a bigger divide between religious believers and modern secular people, to whom it staggers the imagination that anyone could entertain such beliefs. No other feature creates a bigger divide between believers in two different religions, each of whom firmly believes its own beliefs but considers it absurd that the other religion’s believers believe those other beliefs. 

Yep, to believers in one religion, their own strangeness is not strange at all, but only the other religions' claims are bizarre!  (I wonder if Diamond did not choose to highlight Islam because of concerns over potential backlash, or if that was merely an accident.  Nonetheless, it is a notable exclusion in his examples.)

So, why the strange beliefs?
 Blame it on our old tribal cultures, when a system might have been needed in order to figure out the friend from a foe:

If you claim that the founder of your church had been conceived by normal sexual intercourse between his mother and father, anyone else would believe that too, and you’ve done nothing to demonstrate your commitment to your church. But if you insist, despite all evidence to the contrary, that he was born of a virgin birth, and nobody has been able to shake you of that irrational belief after many decades of your life, then your fellow believers will feel much more confident that you’ll persist in your belief and can be trusted not to abandon your group.

Islam does this in an interesting manner, right, by requiring its believers to loudly and openly declare their faith--the Shahada.  Imagine if one is unwilling to assert that faith aloud--it is the mark of an infidel.

India is, of course, always picturesque landscape of believers, and perhaps the Hindu ascetics offer some stunning visuals.  One of these days, I know I will visit Varanasi, to check out the campus from where grandfather earned his metallurgical engineering degree, but to also get a ground-level feel for what drives such strong beliefs, especially for ascetics like the one photographed (from this collection):

An added advantage of going to Varanasi is a variation of that old Pascal logic--might as well get brownie points for going to one of the holiest cities just in case there is a heaven where such matters count :)