Consider the Westboro Baptist Church.
Clearly these people fall into the category of "religious fanatics" and not into the category in which you place yourself, but you're not being honest with yourself if you think that the benefits of supporting an institution like Christianity come independently from the negative outcomes. That might be true if Church leaderships were advancing our conception of morality and ethics instead of digging in their heels and refusing to be dragged any further from their Bronze Age piety than they absolutely-must-be dragged. Even "liberal" major Christian churches (whom many of you would accuse of being way off the mark already) are far more resistant to gay rights and many other things that we really should have figured out by the dawn of the 21st century than the average secular person or group (there was a recent decision in the Methodist church which highlights this easily).
The "fanatics" are the ones running the show because they are the ones who take this seriously enough to devote their lives to it, and they will always be supported by people like you who lend any credibility to the Bible. You remember the Bible, that book which advocates a much crazier version of morality than anything we're even discussing today. As long as you call yourself a Christian and revere the book which you refuse to read honestly, our society will have only so far to climb before the links to the old ways of thinking become strained. The Word is the Rock, as they say, but it's tied to our ankles and the water is rising.
Those of you who claim that clinging to religion has benefits that outweigh the obvious costs are perpetuating its existence more than the true believers. You probably know as I do that there are no good reasons to believe in God (you may even speak in such riddles as "God couldn't just reveal himself, that would take away our free will!" Consider the wealth of evidence supporting any scientific theory, and then realize that there is always some group utilizing their free will to disbelieve it and you'll soon stop talking in this manner). The thing keeping faith alive is the belief that it is somehow necessary or useful, and that without it society would collapse. I cannot recommend to you the book "Breaking the Spell" by Dan Dennett enough. Enjoy the first 3:05 of this video as a primer.
This is why I think it's important to openly demonstrate that society and morality do not collapse without religion, but actually are enriched by the freedom of thought and advances in moral understanding that come from more people digesting these questions for themselves instead of regurgitating rotten rules from the past. The best thing you can do is actually something that you will probably not be appalled by me suggesting:
Read your Bible.
Read all of it and consider it deeply. Find all of the verses that atheists have pointed out to you "out of context" and search for the context in which God found it appropriate to send two she-bears to maul 42 children to death for mocking the alopecia of his prophet Elijah, or literally kill everyone in the world but Noah and his family, or order the genocide and rape of entire civilizations, or condemn to eternal torture billions of people whom He created knowing that they would fail Him and in what ways. Try to rationalize it for yourself, and then just consider for a moment how much effort you're expending trying to formulate a casuistry capable of resolving the stupendous moral tensions you created completely artificially, solely for the sake of maintaining your status quo.
Consider this effort, and imagine how better spent it would be resolving actual moral questions.