I have not once in my life heard someone ask "what was she wearing?" upon learning that someone was raped. I don't doubt that there are some people in the world who react this way but I don't believe for a minute it is most people, or even very many people who do.
As far as warning girls more than boys about sex, I suppose that is true but it seems more practical than sexist or rape culture related. It is the girl who has the potential to get pregnant, not the guy.
Now I am speaking from a North American perspective as opposed to Africa and Nigeria in particular so I don't doubt things are different there but I do hear the same "rape culture" accusations here. No doubt there are plenty of sexist individuals and even rapists in the world, but here at least there is no "culture" of rape as anything remotely acceptable or excusable.
It may just be where you are from nut I have @darth-azrael