1. There's lots going on psychologically in a rape situation. You may not dare scream for fear of being injured, you may be paralyzed by the shock when you realize what's happening to you, you may be unable to scream because your assailant holds a hand over your mouth... etc. etc. etc. And yes, I'm saying 'you', not 'the girl'. Everyone can get raped, man, woman, Christians, rich, beggar, child, adult. Anyone. It's not something that only happens to slutty atheist women who doesn't love God enough to keep their legs together.
2. Screaming doesn't necessarily produce help. There was a case some time ago where a woman was raped downtown in my city, relatively early at night. She screamed for help and received none, even though loads of people were out and about and must have heard her. I hope they're feeling damned proud of themselves today.
3. Rape, by definition, is INVOLUNTARY sex. I don't care how disgusting and Sinful fundies find women having sex - if it's INVOLUNTARY, it's not their fucking fault. Stop making up disgusting excuses like 'oh, she was dressing immodestly', or 'she didn't offer resistance', or 'she shouldn't have walked alone'. That's bullshit and you know it, otherwise you'd have applied it all across the board (imagine a fundie saying that it's the shop owner's own fault he gets robbed if he offered no physical resistance to the robber. Or that it's the 9/11 victims' own fault they died since they were dumb enough to get on an airplane, which they knew was at risk of hijacking).
This put me this close to putting up a rape awareness group on Facebook with lots of facts, links, discussion topics, a Common Myths Dispelled section, etc. But since I know that creating such a group will attract tons of idiots such as this guy, whom I and the other group admins will then have to deal with... I won't. I'd end up losing my temper, hunting them down... you get the idea.