YOU WANT THE TRUTH?! YOU CAN'T HANDLE THE TRUTH!
- Colonel Nathan Jessup (Jack Nicholson) in A Few Good Men.
Yeah ok so I'm too daft to quote some Nietzsche-esque philosophy which would so eloquently express my feelings about this scenario. So sue me :p
This issue is a hybrid form of the maxim ignorance is bliss. Without hesitation I pound my gravel and say yes. I believe we should serve the truth. It is cruel, and it is harsh, but it's the fucking truth. This alone is of the most basic, most intrinsic, and the most fundamental importance.
Coming back to the idea that ignorance is bliss. This is quite simply true. We are happier off being unaware that as we speak people around the world are dieing from famine and war. Is this an evil thing? No. In this case ignorance is not sinful. However when you purposefully make (or keep) people ignorant of something just to keep them happy, that may not be evil or sinful per se, but there is something wrong in it.
Sure it will make them unhappy, it will possibly destroy their most holy and sacred beliefs, but the truth shall set you free - but first it shall make you miserable. Or maybe not. Nevertheless, in this case the truth overrides this false happiness of the followers of the religion. It's wrong to keep people ignorant. Even if the truth is hurtful. If you do where do you draw the line? Can we then suppress the truth because it makes us unhappy? Shall we deny the holocaust because it disturbs us?
Telling people the truth is of the most fundamental importance. We cannot just suppress the truth based on how people will react. We do not have the right to determine a people's happiness. That means that we do not necessarily have the right to make them unhappy. But we do not have the right to keep them ignorantly blissful either. What should we do? Give them the truth.
What is it that we offer in return after taking their happienss away? The truth.
This argument was made with the basis that (1) there was a religion, and somehow you managed to prove that it was false, and (2) this hypothetical "truth" is straightforward factual and not based on personal opinion belief.
I don't have the mental capacity to argue otherwise :p