YABU.
I wouldn't walk on my own after dark. And I don't buy into the male protector thing, I would be happier in a group, whether that be male or female. Walking alone just seems a stupid, unnecessary risk.
Of course I should have the right to stroll down the street in the middle of the night safely, and I shouldn't be attacked. Of course I'm not the one in the wrong if someone does attack me. But that's not really the point. Being attacked is a clear risk. If you feel the benefits of walking outweigh the risk of being attacked, then great, that's your choice. Personally, I would be happier in a taxi.
This PDF has some really interesting analysis of statistics.
Sure, men are more likely to be victims of violent crime, but men are more likely to take risks (walking alone at night, when drunk for example). 2.3% of women become a victim of violent crime every year. A third of this is by stranger, another third domestic and another third by acquaintance. So at least one in a hundred women suffers a violent attack outside the home. Interestingly, people who go to pubs more than once a week have double the risk of being attacked than people who don't go. There is a clear risk there. It's a small risk, but it is significant.
Re: Self defence...
Isn't telling women that they should do some martial arts buying into the blame-the-victim thing as much as anything else?
Sure, martial arts are 'good for you' but there is an implication that if you're unfit or haven't given up hours of your life to learn a specialist skill, you're less deserving of safety on the streets.
Besides which, I don't think a bit of self-defence will necessarily help that much against a knife (or where I am, a gun).