I think you're proving GP's point. The very thought of conceding that there may be a positive side to Christianity (anything! no matter how small!) has you going on about its "unarguable ethical and social flaws." These may indeed be grave. But this don't even begin to justify your implicit contention that there is no positive side to Christianity.

I think the truth is actually pretty obvious: Christianity had both good sides and unarguable ethical and social flaws.