Separating sex from lifelong married commitment is really a detriment to a society, because it diminishes the basic building block institutions of marriage and family.
So, contraception, in and of itself, is amoral, but how it is used certainly a moral question.
It has to be taken on a case by case basis. Having sex out of wed lock is amoral, from a Christian point of view, regardless of contraception. I don't see where contraception is amoral, it is a tool, like a gun, that accomplishes a function. Tools are not amoral but how they are used can be.