Why Is Victim Blaming So Common?

You offer some very valid points...but in the last two scenarios there's some issues. Rihanna keeps going back to Chris Brown. If something happens to her again, is it not partially her fault? I'm sure she has friends and advisers telling her to stay the hell away from him and she refuses to take their advice. As for Roman Polanski, "the victim" has said she was the one who seduced him...so, I dunno if there should be some sort of limitation from his ban from the United States. It was wrong at the time and his punishment was just. He decided to flee the country instead of facing his punishment...but it's 40 years later now and the victim says she wasn't a victim, so maybe it's time to let him come back.

Why is victim blaming so common? Where to begin?!

I think the main reason is that many people are completely ignorant of what consent actually means. All it boils down to is:

Does person A want to have sex?
Yes: sex = consensual
No/unable to give consent (e.g. unconscious): sex = rape

Any other factors - clothing, alcohol consumption, sexual history, etc etc - have nothing to do with it. But when is this ever taught in sex ed classes? When do the police, the media or anyone else ever discard these factors and focus solely the perpetrator's actions?

Also, our culture says, "Women! You must do x, y and z to avoid getting raped," instead of "Men! Don't rape women*," so this tells us that the responsibility for rape lies with the victim, not the rapist.

*Or other men.

This analogy illustrates how ludicrous victim blaming is:

The law discriminates against rape victims in a manner which would not be tolerated by victims of any other crime. In the following example, a holdup victim is asked questions similar in form to those usually asked a victim of rape.

“Mr. Smith, you were held up at gunpoint on the corner of 16th and Locust?”
“Yes.”
“Did you struggle with the robber?”
“No.”
“Why not?”
“He was armed.”
“Then you made a conscious decision to comply with his demands rather than to resist?”
“Yes.”
“Did you scream? Cry out?”
“No. I was afraid.”
“I see. Have you ever been held up before?”
“No.”
“Have you ever given money away?”
“Yes, of course–”
“And did you do so willingly?”
“What are you getting at?”
“Well, let’s put it like this, Mr. Smith. You’ve given away money in the past–in fact, you have quite a reputation for philanthropy. How can we be sure that you weren’t contriving to have your money taken from you by force?”
“Listen, if I wanted–”
“Never mind. What time did this holdup take place, Mr. Smith?”
“About 11 p.m.”
“You were out on the streets at 11 p.m.? Doing what?”
“Just walking.”
“Just walking? You know it’s dangerous being out on the street that late at night. Weren’t you aware that you could have been held up?”
“I hadn’t thought about it.”
“What were you wearing at the time, Mr. Smith?”
“Let’s see. A suit. Yes, a suit.”
“An expensive suit?”
“Well–yes.”
“In other words, Mr. Smith, you were walking around the streets late at night in a suit that practically advertised the fact that you might be a good target for some easy money, isn’t that so? I mean, if we didn’t know better, Mr. Smith, we might even think you were asking for this to happen, mightn’t we?”
“Look, can’t we talk about the past history of the guy who did this to me?”
“I’m afraid not, Mr. Smith. I don’t think you would want to violate his rights, now, would you?”

Victim blaming is so common because it's a way to justify what crimes these men commit. It excuses their disgusting acts, therefore never educating society on what is right and what is wrong.
It could also be known as the "Just World Theory" because people who believe we live in a just world know that rape only happens to girls who act bad. If a girl wears revealing clothing, flirts at bars or nightclubs, walks around late at night, goes back to a guy's house or invites him to her's, she is asking to be raped. When people believe these vile ridiculous myths, it puts them at ease to know they will never be raped if they avoid doing those things mentioned above. To me it's just plain stupid.
I was raped in the Marine Corps and I was blamed up and down for being acquainted with the guy and allowing him into my barracks. We worked together! He was a nice guy, or so I thought, so I was being courteous. Yet I'm the bad guy because I made a nice gesture, and I was being friendly by allowing him into my barracks.
It just disgusts me that society places NO blame on the men because they supposedly have needs that need to be met all the while women are the ones who are supposed to act accordingly.
Sorry for the rant, but that is the best way I can describe it. I hope this helped.

"All we have to decide is what to do with the time that is given to us." -Gandalf the Grey

Some of those stories are just horrible. Human beings are vile. Victim blaming is partly people not wanting to think this can happen to them so they make themselves feel better by telling themselves it can only to happen to stupid or worthless people. Rapists and sex offenders are also often very convincing, charming people so when they rape someone people don't want to see them for what they are so try to put blame on the victim or call the victim a liar. Society also has a very negative view of womens sexuality so when a woman who is anything other chaste is raped some people view her as less worthy of respect as a "decent" woman so not as deserving of sympathy.

I don't know. Why do you think it is common?

I think victim blaming is common in every sort of wrongdoing, not just rape, and not just by men, but women too.

As an example, I had a friend who was dating a married man. I told her that's not a good idea, that she should find someone who's genuinely available and respect the boundaries of marriage, but she justified it by saying that the wife isn't good for him! I also told her that a man who can cheat on his wife will probably cheat on her at some point, but she justified that by saying that he wouldn't do that to her (again thinking that she's somehow so much better than the wife).

This is a case of a woman blaming the victim of the affair for the cause of it, and it's not uncommon to see this type of thing happening because humans are selfish, egotistical creatures who like to give excuses to justify any viewpoint they have.

Now, one of the reasons I think rape and sexual harassment are so subject to questioning and possibly even blaming the victim is that it relies almost entirely on eyewitness testimony of the victim. The difference between what's consensual often solely rests on the perceptions of the victim, and the perceptions of a single person, as we know, are very unreliable.

Meanwhile, this is going to come off as sexist, but law enforcement officials understand that eye witness testimonies of women tend to be more unreliable than men in general. This is just plain fact, and it's for reasons which can be explained psychologically and biologically: women tend to be more emotional creatures, and emotion is the general cause of bias and an obstruction of truth. In fact, we can find a lot of evidence that women lie and cheat even more often than men even though society generally applies a lot of double standards there and make it out as though men are more deceptive than women when often the opposite is true.

And this is made far worse by the likes of Harlequin novels. I read some passages and was astounded: I was reading a rape scene! The man tries to have sex with a woman, she resists, he continues. That's rape! Yet the female authors of these novels insist that this is not rape because even though the woman said "no", she actually meant "yes". She wanted this to happen to her even though she resisted (she resisted only because she wanted to act innocent), so it was actually a consensual act even though it looks like a clear cut case of rape!

Do you know how seriously confusing this is to a man?!! I think women need to do a better job of communicating their thoughts and feelings more directly. There's far too much ambiguity if we can't even tell what does and doesn't count as consent. Maybe women should just start going up to guys and saying, "Hey, I want to have sex with you." Part of the reason rape and sexual harassment is so filled with ambiguities is because of the lack of direct communication when it comes to courtship.

Harlequin novels typically contain a rape fantasy of some sort, and when we know that rape fantasies exist (and not among a trivial minority), and when we also find real cases where men have been put in prison because of rape accusations and later found innocent, then naturally we have to question the victim quite thoroughly, and that could cross over into what is construed as blaming the victim.

It is common because we live in a mostly Patriarchal society (read: ruled mostly by males) and that in all cases involving sexual activity, males get deferential treatment automatically. The rationale for this is astonishingly horrifying: we as males have no "choice" but to act due to our hormones going out of control and our sex drive being so powerful. As if we have no free will at all, and "boys will be boys". Which is of course utter nonsense. If a man can't control his sexual urges he needs professional treatment/help, in the form of drugs/therapy/hospitalization.

It's pathetic how much energy is invested in blaming victims of rape instead of rapists. But really it's just about avoiding responsibility or simply ignoring the problem, which is what some people will do with any victim. You can't read a news report about police brutality without someone calling the victim a thug or saying they deserved it. You won't be able to read a story about a woman reporting domestic abuse without also reading accusations that she's faking it.