I think my girlfriend and her friend's constant fear of rape and assault if irrational
Why do you think that is not a rational concern?
Feminism makes them think that they can be attacked at any time.
Even if you don't think they should be scared of that, you don't know how it feels for women. Even if it might be a little irrational, it could still happen and it is good to be careful.
I think that a woman not being raped is the same as an ugly girl not getting raped, like it rarely happens and if it does, it's her fault.
That is unfair of you to say. How would you feel if it was your mother or sister being assaulted? Rape is about the perpetrator wanting to feel powerful, the person being assaulted is in no way to blame for it.