It's not defensive mode but simple disagreement.
Thinking about it, in fact often the opposite is the case.
In areas were women tend to be extremely dominant, the insecure and rather self-loathing men are preferred and confident men are often shunned (well if they're big, they get used for one night stands and thrown away, but I wouldn't want that either).
Ha, I could get you a bloody lot of examples of the opposite here as well. The less flaws you have, the more others tend to be humbled by it and their own insecurites get a boost which isn't giving them a good feeling even if you encourage them all the time and try to help them to focus on their talents. I've heard this from several ex-gfs of mine directly and seen it everywhere. Of course people in this city here are screwed up big time anyway and my generation has problems with any relationship that goes beyond the most superficial layer in general.
Thinking about the extremely few holding relationships in my surroundings, the guys are always earning a lot of money and are kind of saggy submissive dummies.
There are reasons for that:
http://www.bbc.com/news/world-europe-32929962