Christianity, or any other religion, isn't outright good or outright bad - it's a neutral tool which can be used to be either beneficial or detrimental to society. Unfortunately, most of history has resulted in it being misused.
The only problem with religion is that it can lead to people believing life is pointless (because they think that we only exist to do good and get into heaven), and plus you get denominations like the Catholic church going out and telling Africans that contraception is bad, when it would help them greatly with the AIDS pandemic and massive over-population.