@Mr_NutterButter
I do hear this argument quite often, but here would be my argument against it.
1) I do not believe, that this does make people act moral. I went to a christian primary school, and the nihilism there was exactly the same as outside of it. The christians didn't seem to be actually driven by that ideology in any meaningful way, and the only thing it did create was an in-group out-group dynamic. (that can be good, but only, if the group is the correct size and internally enpathetic)

2) this description sounds to me like the lowest possible form of "survival level" morality with no space to grow. If you believe, that christianity serves this, I can accept it, but using this argument puts it on the same level as moral fast food.