I'm pretty sure you don't need to believe in God to consider rape and murder unethical, immoral, and just wrong. In fact, plenty of people have pointed out (repeatedly) the fallacy of assuming that one needs God and/or religion to be good, so there is no reason to say more on that topic here. Go forth and Google.
The culture of consent and contraception, leads to this.
I'm not sure what the "culture of contraception" is, but I am pretty sure it does not lead to this kind of behavior, either. In fact, I strongly suspect this behavior - in general, minus the Internet - predates the widespread availability of contraception.